Myoepithelial Neoplasms of Soft Tissue: An Updated Review of the Clinicopathologic,Immunophenotypic, and Genetic Features

Myoepithelial tumors in skin and soft tissue are uncommon but have been increasingly characterized over the past decade. Men and women are equally affected across all age groups and lesions arise most frequently on the extremities and limb girdles. Approximately 20 % of cases occur in pediatric patients, in whom they are frequently malignant. Similar to their salivary gland counterparts, myoepithelial tumors of soft tissue demonstrate heterogeneous morphologic and immunophenotypic features. Tumors are classified as mixed tumor/chondroid syringoma, myoepithelioma, and myoepithelial carcinoma; in soft tissue, tumors having at least moderate cytologic atypia are classified as malignant. Mixed tumor and myoepithelioma show a benign clinical course, with recurrence in up to 20 % (typically secondary to incomplete excision), and do not metastasize. In contrast, myoepithelial carcinoma shows more aggressive behavior with recurrence and metastasis in up to 40–50 % of cases. The majority of myoepithelial neoplasms typically coexpress epithelial antigens (cytokeratin and/or EMA) and S-100 protein; GFAP and p63 are frequently positive and a subset of malignant neoplasms lose INI1 expression. Up to 45 % of myoepitheliomas and myoepithelial carcinomas harbor EWSR1 gene rearrangements, unlike mixed tumor/chondroid syringoma which is characterized by PLAG1 gene rearrangement. While mixed tumor/chondroid syringoma are likely related to primary salivary myoepithelial tumors, soft tissue myoepithelioma and myoepithelial carcinoma appear to be pathologically distinct neoplasms.     

Myoepithelial carcinoma of soft tissue in children: an aggressive neoplasm analyzed in a series of 29 cases

Primary myoepithelial tumors of soft tissue are uncommon, and criteria for malignancy among these neoplasms have only recently been established. Of 51 myoepithelial carcinomas of soft tissue in the literature, 11 occurred in children, 7 of which were included in a previous series of myoepithelial tumors from our group. We have collected an additional 22 cases of myoepithelial carcinoma of soft tissue in the pediatric population, and we describe the detailed clinicopathologic features of all 29 cases herein. There were 15 girls and 14 boys; age at diagnosis ranged from newborn to 17 years (median, 9 y). Sites included extremities (14 cases), trunk (6 cases), viscera (5 cases: 3 mediastinal, 1 retroperitoneal, and 1 intracardiac), and head/neck (4 cases). Histologically, the tumors were heterogeneous, with epithelioid, clear, spindle and/or plasmacytoid cells forming nests, cords or solid sheets in a myxoid or hyalinized stroma. Epithelioid cells predominated in the majority of cases (27 of 29; 93%) and in 10 cases (34%), tumor cells focally had scant cytoplasm with round cell morphology. The mitotic rate ranged from <1 to 68 per 10 high power fields (median, 8), and tumor necrosis was present in 14 cases. At least 1 broad-spectrum cytokeratin was positive in all tumors [CAM5.2 in 17 of 18 (94%), AE1/AE3 in 15 of 20 (75%), and PAN-K in 14 of 21 (67%)], and EMA was positive in 19 of 29 cases (66%). Either S100 or GFAP was positive in all but 4 cases [S100 in 21 of 29 (72%) and GFAP in 15 of 28 (54%)]. Clinical follow-up in 23 cases revealed that 9 patients had local recurrences (53% of the 17 patients who underwent complete excision with negative margins); 12 (52%) developed metastases; and 10 (43%) have died of disease so far, at a median interval of 9 months after diagnosis. Despite the relative rarity of carcinomas in the pediatric population, myoepithelial carcinoma seems to be disproportionately common among children and often has an aggressive clinical course.     

Myoepithelial Carcinoma Ex Pleomorphic Adenoma of the Maxillary Sinus: A Case Report and Review of Literature

Myoepithelial carcinoma ex pleomorphic adenoma is defined as a malignant epithelial neoplasm arising from a primary or recurrent benign pleomorphic adenoma. This type of tumor comprises 3.6% of all salivary gland tumors and 12% of malignant ones. Clinically, it most commonly presents as a firm mass in the parotid gland. The development of this neoplasm in the sinonasal and nasopharyngeal regions is extremely rare and only few cases are reported in the literature. The prognosis of myoepithelial carcinoma is variable. Marked cellular pleomorphism, high mitotic rate, and high proliferative activity correspond to a poor prognosis. In this article, the authors report the histopathological features of a clinical case of a 64-years-old patient with a large median maxillary neoplasm diagnosed as myoepithelial carcinoma/ex-pleomorphic adenoma. The tumor was resected and subjected to secondary reconstruction using a revascularized free fibula flap. The myoepithelial derivation of neoplastic cells was demonstrated by immunohistochemical positivity for S-100 protein (strong and diffuse), cytokeratin 14 (strong and diffuse), and GFAP (focal).     

Myoepithelial tumors of soft tissue: a clinicopathologic and immunohistochemical study of 101 cases with evaluation of prognostic parameters

Myoepitheliomas and mixed tumors were only recently recognized to occur primarily in soft tissue, and only small case numbers have been described. To characterize these tumors further and to evaluate prognostic parameters, 101 myoepithelial tumors of soft tissue were retrieved from the authors' consult files. Hematoxylin and eosin sections were reexamined, immunohistochemistry was performed, and clinical details were obtained from referring physicians. Fifty-three patients were male and 48 female (mean age 38 years; range 3-83 years). Tumor size ranged from 0.7 to 20 cm (mean 4.7 cm). Most tumors arose in the extremities and limb girdles: 41 in the lower limbs, 35 in the upper limbs, 15 in the head and neck, and 10 in the trunk. Fifty-four tumors were situated in subcutis and 37 in deep soft tissue (depth unstated in 10). Most cases were grossly well circumscribed; 43 showed microscopically infiltrative margins. Histologically, most tumors were lobulated, composed of cords or nests of epithelioid, ovoid, or spindled cells with a variably reticular architecture and a chondromyxoid or collagenous/hyalinized stroma. Eight cases showed a predominantly solid proliferation of spindled or plasmacytoid cells; 17 demonstrated ductular differentiation (mixed tumors). Cartilage was present in 6 cases, 6 contained bone, and 4 others contained both. Mitoses ranged from 0 to 68 per 10 high power fields (mean 4.7 per 10 high power fields). Tumors with benign cytomorphology or mild cytologic atypia (low-grade) were classified as myoepithelioma or mixed tumor, whereas tumors with moderate to severe atypia (high-grade) were classified as myoepithelial carcinoma (epithelioid or spindled cells with vesicular or coarse chromatin, prominent, often large nucleoli, or nuclear pleomorphism) or malignant mixed tumor (cytologically malignant cartilage or bone). Sixty-one cases were myoepitheliomas or mixed tumors, and 40 were myoepithelial carcinomas or malignant mixed tumors. By immunohistochemistry, all cases with available material were reactive for epithelial markers (keratins and/or epithelial membrane antigen): 90 of 97 (93%) expressed keratins (most often AE1/AE3 or PAN-K), 84 of 97 (87%) S-100 protein, 44 of 51 (86%) calponin, 52 of 83 (63%) epithelial membrane antigen, 40 of 87 (46%) glial fibrillary acidic protein, 27 of 75 (36%) smooth muscle actin, 15 of 66 (23%) p63, and 7 of 51 (14%) desmin. Follow-up was available for 64 patients. Among 33 cases with benign or low-grade cytology (mean follow-up 36 months; range 4-168 months), 6 recurred locally (18%) and none metastasized. No clinical or histologic features correlated with recurrence. Among 31 cytologically malignant cases (mean follow-up 50 months; range 4-252 months), 13 recurred locally (42%) and 10 metastasized (32%); so far, 4 patients have died of metastatic tumor. This study expands the spectrum of myoepithelial tumors of soft tissue to include myoepithelial carcinomas and malignant mixed tumors, which pursue an aggressive clinical course. Although the majority of morphologically benign or low-grade myoepithelial neoplasms of soft tissue behave in a benign fashion, there is an approximate 20% risk for local recurrence.     

Histogenesis of benign pleomorphic adenoma (mixed tumor) of the major salivary glands. An ultrastructural and immunohistochemical study

Twenty-two benign pleomorphic adenomas of the major salivary glands were studied by transmission electron microscopy and immunohistochemical techniques (three cases) in order to characterize the cell types comprising the epithelial and so-called mesenchymal regions of the tumors. Light- and electron-microscopic studies showed the tumors to consist of variable mixtures of neoplastic ductular epithelial cells, rare acinar cells, and metaplastic myoepithelial cells. Many of the loosely organized "stromal cells" contained structures indicative of their myoepithelial origin, e.g., perinuclear tonofilaments, ectoplasmic actin microfilaments, and remnants of basement membrane. Polyclonal antikeratin antisera strongly stained ductular epithelial and myoepithelial cells, squamoid cell nests, and periductular myoepithelial cells, whereas myxoid and chondroid cells were less intensely stained. Monoclonal cytokeratin antibody AE1 stained only the ductular epithelial cells in both the normal glands and tumors. In contrast, S-100 protein, which is present only in scattered acinar cells and myoepithelial cells in the normal parotid gland, was found in the ductular and periductular myoepithelial cells, isolated myxoid cells, and chondroid and cartilagenous cells in the tumors. Actin was found in all the cell types of the tumor but staining was strongest in the ducts. Double immunofluorescence staining for cytokeratin and vimentin revealed coexpression of both types of intermediate filaments in occasional normal acinar and intercalated duct myoepithelial cells, and in some cells in the myxoid and chondroid regions of the tumors. In the tumors, vimentin was present in occasional periductular myoepithelial cells, stellate myxoid cells, and especially in chondroid cells and chondrocytes. Our findings indicate that benign pleomorphic adenomas of the major salivary glands are pure epithelial cell tumors. The histologic complexity of these neoplasms is due to the ability of the neoplastic ductular myoepithelial cell to modulate its morphologic appearance and intermediate filament composition, and to produce large amounts of matrix substances. We further postulate that these tumors arise from neoplastically transformed intercalated ducts.     

Sclerosing adenosis of the prostate gland. A lesion showing myoepithelial differentiation.

Sclerosing adenosis of the prostate is a rare lesion characterized by the proliferation of variably sized glands in a cellular stroma. We report light microscopic, immunohistochemical, and ultrastructural studies in 22 examples from 15 patients. Two cases were identified in 100 consecutive prostates embedded by a whole organ method, giving a prevalence of 2%. Antibodies directed against the following antigens were used: high-molecular-weight cytokeratin (CKH; 34 beta E12); cytokeratin (CK; AE1/AE3), prostatic acid phosphatase (PAP), prostate-specific antigen (PSA), S-100 protein, muscle-specific actin (HHF35), and vimentin (Vim). Cells within the glandular component demonstrated positive reactivity for CK, CHH, PSA, and PAP, indicating a prostatic epithelial origin. In addition, a distinct population of cells reacting for muscle-specific actin and S-100 protein was identified within this glandular element. Adequate material for ultrastructural study was available in five cases; all showed the presence of flattened cells located between the basement membrane and secretory epithelial cells, which had features typical for myoepithelial differentiation. Although the prostate gland does not normally contain myoepithelial cells, we have documented their consistent presence in this unusual lesion; we believe these cells arise by a metaplastic process from the prostatic basal cells.     

Myoepithelial Tumors of Bone

Myoepithelial tumors (METs) of bone (BMETs) are a rare but distinct tumor entity. METs that are cytologically benign are termed myoepitheliomas; METs with malignant histologic features are called myoepithelial carcinomas. BMETs have a wide age range, may involve any part of the skeleton, and have a variable spindle cell and epithelioid morphology. Bone tumors to be considered in the differential diagnosis are discussed. Additional techniques are indispensable to correctly diagnose BMETs. By immunohistochemistry, BMETs often express cytokeratins and/or EMA together with S100, GFAP, or calponin. Half of BMETs harbor EWSR1 (or rare FUS) gene rearrangements with different gene partners.     

Myoepithelial Tumors of Salivary Gland: A Clinicopathologic and Immunohistochemical Study of 15 Patients with MIB-1 Correlation

Myoepithelial neoplasms are rare tumors of the salivary glands with predominant myoepithelial differentiation and a broad histologic spectrum. Their histological features, immunohistochemical profile and biological behavior are not well characterized and pose a diagnostic challenge. A total of 15 myoepithelial tumors, diagnosed during 2012 and 2019 were subcategorized and correlated with MIB-1 labeling index (LI) and various histological parameters. Immunohistochemical stains for MIB-1 and other antibodies were performed. Statistical analysis was done by chi-square test, Fisher’s exact test and Kaplan Meier curve. Nine patients were male and six were female with the median age of 44 years (range 21–83 years). Of the 15 patients, 6 cases were classified as myoepithelioma (ME) and 9 cases as myoepithelial carcinoma (MECA). Parotid gland was the most common site (46.7%) followed by the palate. MEs showed well circumscribed tumor borders whereas MECAs exhibited focal capsular to extensive invasion into adjacent tissues. Epithelioid cell morphology was most common followed by mixed cell morphology. MIB-1 LI was significantly associated with invasive tumor borders, necrosis and high mitosis. Increased frequency of recurrence was noted with high MIB-1 LI, though it was not statistically significant. MIB-1 LI was high in nearly all MECAs with focal capsular to extensive invasion while low in MEs. Myoepithelial tumor with multinodular growth pattern and focal capsular invasion may have an indolent behavior if mitotic activity and MIB-1 LI is low. Early diagnosis and treatment of MECAs significantly improves the patient''s survival and prognosis.     

Cutaneous melanoma with myxoid features: twelve cases with differential diagnosis

Substantial myxoid change can occur in malignant melanoma, but its importance in primary disease has not been systematically evaluated. This report describes the clinical, microscopic, histochemical, and immunohistochemical findings in 12 patients with primary cutaneous malignant melanoma with myxoid features. The tumors presented as solitary lesions situated on the limbs (six lesions), trunk (four lesions), and head and neck (two lesions). The patients included six women and six men, whose ages ranged from 26 to 95 years, with a mean of 63 years. Breslow thickness varied from 0.48 mm to more than 12 mm, with a mean of more than 3.2 mm. Clinical follow-up for an average of 22 months showed one local recurrence, but no evidence of metastases yet. In all cases, there was a combination of myxoid and nonmyxoid areas. A minimum of 15% myxoid cross-sectional area was required for inclusion in the study, and up to 80% was observed. The pale blue mucin identified on hematoxylin and eosin staining was sensitive to hyaluronidase and positive for alcian blue in the 10 cases stained. Immunohistochemical staining was positive for S-100 in all 9 cases stained, positive for HMB-45 in 9 (90%) of 10, and negative for cytokeratin in all 9 cases in which myxoid melanoma remained in the block after previous sections. The presence of myxoid stroma did not define a biologically significant subgroup of melanoma. Only in cases with extensive (>50%) myxoid stromal effacement of the melanoma was there a major diagnostic hurdle. The diagnosis of primary cutaneous melanoma with myxoid features was seldom as problematic as metastatic myxoid melanoma. Positive S-100 stains, negative cytokeratin immunohistochemical stains, and hyaluronidase-sensitive alcian blue staining assisted in the diagnosis of this entity.     

Sebaceous epithelial-myoepithelial carcinoma of the salivary gland: clinicopathologic and immunohistochemical analysis of 6 cases of a new histologic variant

Epithelial-myoepithelial carcinoma (EMC) of the salivary glands is an uncommon, low-grade malignant tumor. A recent report demonstrates sebaceous differentiation in this tumor even though its significance has never been documented as a precise histologic variant. Six cases of EMC exhibiting sebaceous differentiation (sebaceous EMC) of the parotid gland were analyzed for their clinicopathologic features and immunohistochemical characteristics. In addition, primary salivary sebaceous carcinomas were also examined for comparison. In our series, the incidence of sebaceous EMC was 0.2% among 3012 cases of parotid gland tumors and 14.3% of all EMC cases. The 6 patients comprised 2 men and 4 women, age ranging from 77 to 93 years (mean, 83.7 y). Neither cervical lymph node nor distant organ metastases were found in any cases of sebaceous EMC and no patients died of disease, though local recurrences developed in 1 patient. Conversely, cervical lymph node metastasis was detected in 2 of 3 patients with sebaceous carcinoma, 1 of whom died of disease at 12 months. Histologically, all 6 tumors had an area of sebaceous differentiation admixed with features of bilayered ductal structures typical of EMC. A component of sebaceous differentiation was distributed diffusely in 4 tumors and focally in 2. Cytologic atypia of sebaceous EMCs was lesser than that of sebaceous carcinomas. Immunohistochemically, putative myoepithelial markers such as alpha-smooth muscle actin, calponin, p63, cytokeratin 14, S-100 protein, and vimentin were highly expressed in sebaceous EMC. However, the expression of the latter 4 markers was also observed in primary sebaceous carcinomas, whereas these tumors were all negative for alpha-smooth muscle actin and calponin. Positive immunoreactivity for epithelial membrane antigen, adipophilin, and perilipin confirmed sebaceous differentiation in EMC. These results indicate that sebaceous EMC is a low-grade malignancy, similar to conventional EMC. Our data also suggest that immunohistochemical examination of specific myoepithelial markers is helpful in distinguishing sebaceous EMC from sebaceous carcinoma, which may occasionally be associated with an aggressive clinical course.     

Myoepithelial Carcinoma: A Rare Neoplasm of the Breast

BACKGROUND: Malignant myoepitheliomas of the breast are extremely rare. There has been a limited number of published reports of myoepithelial carcinomas originating from the breast. CASE REPORT: We describe a malignant myoepithelioma of the breast in a 56-year-old woman. Histological examination showed polygonal epithelioid cells and spindle cells with moderate to marked nuclear atypia. Immunohistochemistry showed reactivity in the spindle cells for smooth muscle actin, cytokeratin (AE1/AE3), and p63, indicating a myoepithelial cell lineage of tumor cells. The patient underwent radical surgical excision of the lesion and axillary lymph node dissection. She demonstrated no evidence of recurrence over an 11-month follow-up. CONCLUSIONS: We suggest myoepithelial carcinomas of the breast be managed with appropriate surgical clearance. A multidisciplinary approach is usually required.     

Salivary gland-type tumors with myoepithelial differentiation arising in pulmonary hamartoma: report of 2 cases of a hitherto unrecognized association

Reported is a hitherto unrecognized association of pulmonary hamartomas with salivary gland-type tumors showing myoepithelial differentiation, namely, a case of myoepithelioma arising in a otherwise classic hamartoma with cartilage predominance, and a case of malignant mixed tumor arising in a predominantly fibrous hamartoma resembling müllerian adenofibroma. The tumors occurred in middle-aged female patients of 35 and 44 years, respectively, and presented as 7 cm (treated with lobectomy) and 13 cm (treated with pneumonectomy) masses of the right upper lobe showing a short clinical history of cough, dyspnea, and wheezing. Both lesions did not present regional lymph node metastases after mediastinal lymphadenectomy. The myoepithelioma patient was well with no signs of recurrent disease at 6-month clinical control, but she was then lost to follow-up; the malignant mixed tumor patient is alive and well after 6 months since operation. Both tumors presented with morphologic and immunohistochemical features of myoepithelial cells, and we interpret them as being derived from a myoepithelial-like stromal cell population found within the hamartomatous areas, which is also consistently detected in classic pulmonary hamartoma. The lack of individual cell necrosis, mitotic activity, cell atypia, and pulmonary parenchyma infiltration supported a diagnosis of benign or unproven malignant potential tumor for the myoepithelioma, whereas the reverse held true for the other tumor in which the diagnosis of malignant mixed tumor of the lung was rendered. Their main importance of recognizing this association lies in separating these tumors histologically from other monophasic or biphasic tumors, either primary or secondary, such as pulmonary sarcomatoid carcinomas or true sarcomas, and metastatic salivary gland tumors, spindle cell carcinomas, melanomas, and soft tissue and visceral sarcomas.     

Spindle cell myoepithelioma of the nasal cavity.

Minor salivary gland neoplasms with mesenchymal-like features are uncommon in the sinonasal tract. We herein report a case of spindle cell myoepithelioma of the nasal cavity in a 69-year-old woman who presented with a rapidly expanding tumor accompanied by episodes of epistaxis. Although initially considered as a mesenchymal neoplasm, ultrastructural and immunophenotypical characterization demonstrated its myoepithelial nature. In the sinonasal setting, this unusual neoplasm may be confused with soft tissue tumors showing spindle cell or myxoid features. Staining for cytokeratin is found to be the most useful adjunct to diagnosis.     

Myoepithelial Carcinoma of the Breast with Focal Rhabdoid Features

Myoepithelial carcinoma of the breast is extremely rare and only 33 cases have been reported in the English literature. Herein, we report a case of myoepithelial carcinoma of the breast with focal rhabdoid features. The patient was a 67‐year‐old woman, who presented with a lump of the left breast that rapidly grew to 3 cm in diameter within 3 months. Lumpectomy revealed a solid and whitish colored tumor, which was composed mainly of elongated spindle‐shaped cells with mild atypia, focal necrosis, and infiltrative margin. In a small area of the lesion, ovoid tumor cells exhibited eccentric nuclei with centrally located nucleoli and plump cytoplasm including round eosinophilic inclusions, resembling a rhabdoid tumor. Immunohistochemically, both types of tumor cells exhibited a myoepithelial phenotype. MIB‐1 index was 30%. The cytoplasmic inclusion of the ovoid cells exhibited immunopositivity for both vimentin and cytokeratin. From these findings, this tumor was diagnosed as a myoepithelial carcinoma with focal rhabdoid features. Although rhabdoid features have been reported in some types of malignant and benign tumors, this is the first report of such features in myoepithelial carcinoma of the breast.     

Small cell carcinoma of the major salivary glands: clinicopathologic study with emphasis on cytokeratin 20 immunoreactivity and clinical outcome

Small cell carcinomas arising in salivary glands, extremely rare high-grade malignant tumors, are subclassified into neuroendocrine and ductal types. The neuroendocrine type may be segregated further into Merkel cell and pulmonary varieties according to cytokeratin 20 immunoreactivity. Whether subclassification of this tumor group has any biologic or clinical significance is not known. We examined 15 cases (11 men, 4 women; mean age, 66.5 years) of small cell carcinoma of major salivary glands from a single institution and analyzed their clinicopathologic profiles, including immunohistochemical features and prognostic factors. Three fourths of small cell carcinomas showed cytokeratin 20-positive immunostaining, often with a paranuclear dotlike pattern of reactivity. All tumors were immunoreactive for at least 2 of 6 neuroendocrine markers examined, and 6 tumors were also positive for neurofilament, with a paranuclear dotlike pattern. Postoperatively, 9 patients developed metastatic disease, and 10 patients died of disease 2 to 45 months (mean, 15.9 months) after diagnosis. By log-rank analysis, overall survival was reduced significantly for patients with a primary tumor larger than 3 cm in diameter (P = 0.032), negative immunostain reaction for cytokeratin 20 (P = 0.012), and decreased immunoreactivity for neuroendocrine markers (P = 0.034). These results indicate that small cell carcinoma of major salivary glands is a highly aggressive tumor, although the prognosis may be better than for extrasalivary neoplasms. Our data also suggest that most salivary gland small cell carcinomas exhibit neuroendocrine differentiation. Immunohistochemical expression of cytokeratin 20 can be used to classify salivary small cell carcinomas into Merkel cell and pulmonary types and may have prognostic significance.     

Myoepithelial Carcinoma Ex-Pleomorphic Adenoma: A Rare Pathology Misdiagnosed as Pleomorphic Adenoma; With a Novel TERT Promoter Mutation and High PD-L1 Expression

Myoepithelial carcinoma (MECA) is a rare salivary gland (SG) neoplasm (0.1–0.45% of all SG tumors) that often presents with bland cytomorphology and can be misclassified as cellular pleomorphic adenoma (PA) or myoepithelioma. This is particularly challenging in MECA ex-PA cases, especially if tumor shows minimal to no capsular invasion. We report a rare case of a 76-year-old female; history of left superficial parotidectomy with diagnosis (outside hospital) of cellular PA, who re-presented 9 months post surgery with enlarging left parotid mass, neck lymphadenopathy and facial nerve deficits. FNAB of parotid and neck lymph node revealed cellular aspirates with loosely cohesive clusters of myoepithelial cells with occasional chondromyxoid stroma. Prior resection slides were reviewed, and diagnosis of MECA ex-PA was made. Patient underwent left radical parotidectomy, selective neck dissection, with facial nerve sacrifice (due to extensive encasing by tumor). Histology showed a multinodular tumor with pushing borders, zonal arrangement comprising of a hypocellular, necrotic/myxoid center, and a peripheral rim of myoepithelial cells, confirmed by positive S100, and p63. Tumor extensively infiltrated peri parotid soft tissues with multiple foci of lymphovascular and perineural invasion; and metastatic neck lymph nodes. Next generation sequencing revealed a novel TERT promoter mutation (c.-124C > T), not usually described in SG neoplasms. Further, PD-L1 immunohistochemistry showed positive expression, making patient eligible for anti-PDL-1 immunotherapy. This case highlights importance of recognizing the subtle malignant features of MECA in distinguishing it from benign mimics like PA. In addition, presence of TERT mutation opens a new arena for future research to explore potential treatment targets.     

Primary Melanoma of the Adrenal Gland,a Continuous Dilemma: Report of a Case

The adrenal gland can frequently be the site of metastatic deposits, including malignant melanocytic tumors; however, primary melanoma of the adrenal gland is exceptional. We reviewed 18 cases reported in the English literature to date, and here add another case which occurred in a 78-year-old man. The patient underwent right suprarenalectomy and the pathology report showed a malignant melanoma of the adrenal gland. Immunohistochemical staining revealed a positive antibody-specific cytoplasmic reactivity to S-100 and HMB-45 proteins with a negative reaction for cytokeratin (AE1, AE3), synaptophysin, chromogranin and neuron-specific enolase. There are diagnostic criteria for accepting an adrenal melanoma as primary; however, an autopsy is the final step to confirm this infrequent pathology.     

Myoepithelial carcinoma of the lung.

Primary lung carcinomas showing features of salivary gland-type neoplasms are rare. Many are mucoepidermoid carcinomas and adenoid cystic carcinomas. Myoepithelial carcinoma of the lung is extremely rare, and in the WHO classification is classified as 'Others' among carcinomas of the salivary gland. The pertinent literature is restricted to a few pathological reports, and hardly any clinical examinations have been performed. Here we report a resected case of myoepithelial carcinoma of the lung, including details of clinical examination, with a review of previously documented cases.     

Mesonephric adenocarcinomas of the uterine cervix: a study of 11 cases with immunohistochemical findings

Mesonephric adenocarcinoma is a rare variant of cervical carcinoma with relatively few, well-documented cases reported. We describe the clinicopathologic and immunohistochemical features of 11 examples of this neoplasm, which occurred in women between the ages of 35 and 72 years (mean, 52 years). Most (64%) patients had abnormal vaginal bleeding. Eight tumors were stage IB, and one each was stage IIB and IVB; in one, the stage was unknown. Microscopically, the carcinomas showed various morphologies, most commonly a small tubular pattern or a ductal pattern resembling endometrioid adenocarcinoma; one tumor had an associated malignant spindle cell component. Ten neoplasms were adjacent to hyperplastic mesonephric remnants. Follow-up in 10 cases showed six patients to be alive without evidence of recurrence after a mean of 4.8 years. The patients with stage IIB and IVB disease had local recurrences after 2.2 and 0.7 years and died of progressive disease at 3.2 and 0.8 years, respectively. In a patient with stage IB disease, a mediastinal metastasis and a malignant pleural effusion developed 5.6 years after diagnosis, and the patient died of disease at 6.2 years. Another patient with stage IB disease and a positive vaginal cuff margin that recurred locally after 1.7 years received chemotherapy and was alive and clinically free of disease at 2.5 years. Mesonephric adenocarcinomas were immunoreactive for epithelial markers (AE1/3; CK1, CAM 5.2, cytokeratin 7, and epithelial membrane antigen) (100%), calretinin (88%), vimentin (70%), androgen receptor (33%), and inhibin (30%, focal staining). No immunostaining was detected with cytokeratin 20, estrogen receptor, progesterone receptor, and monoclonal carcinoembryonic antigen. This staining profile is similar to that of mesonephric remnants and may be useful in the distinction of mesonephric carcinoma from mullerian endometrioid adenocarcinoma, with which it may be confused.     

Comparison of p63 and p73 expression in benign and malignant salivary gland lesions

BACKGROUND: The p63 and p73 genes are members of the p53 family and play an important role in stem cell identity and cellular differentiation and are expressed in basal and myoepithelial cells. In this study, we examined the expression of p63 and p73 in 50 various benign salivary gland lesions and 45 malignant salivary gland tumors. METHODS: The 95 salivary gland tumors were selected from the archives of the Department of Pathology and Laboratory Medicine at the Hospital of the University of Pennsylvania. Sectioned formalin-fixed paraffin-embedded tissue cut at 3 mum was immunostained with antibodies that recognize all isozymes of p63 and p73 and evaluated with respect to percentage of positive cells and localization. RESULTS: In benign lesions, p63 and p73 nuclear reactivity was seen in 46 (92%) of 50 and 47 (94%) of 50 cases, respectively. In malignant tumors, p63 and p73 were seen in 34 (76%) of 45 and 40 (89%) of 45 cases, respectively. A significant difference between p63 and p73 positivity was only seen in adenoid cystic carcinomas (p = .006). Also, p73 was found in tumors with minimal basal/myoepithelial differentiation. CONCLUSIONS: Hence, p63 and p73 expression is retained in both benign and malignant salivary gland tumors with basaloid or myoepithelial differentiation. Hence, p63 seems to be a more specific marker of myoepithelial differentiation than p73.