Adenocarcinoma of the thymus: mucinous subtype

Primary thymic adenocarcinoma, mucinous subtype, is extremely rare with only one case reported to date. We describe herein a case of thymic mucinous adenocarcinoma. A 59-year-old man was identified to have an anterior mediastinal tumor and was diagnosed as mucinous adenocarcinoma. Clinical and radiographic examinations disclosed no evidence of tumor elsewhere. The patient received radiotherapy, but the general condition deteriorated and died 11 months after tumor detection. Thoracic autopsy revealed an anterior mediastinal tumor measuring greater than 10 cm, uncapsulated, and white. The tumor had clear margins and was clearly isolated from the lung. Histologically, the tumor demonstrated papillary, acinar, and cribriform structure and produced abundant extracellular mucin. Immunohistochemically, most tumor cells were positive for cytokeratin 7, were partially positive for CD5, and were negative for TTF-1, Sp-A, CDX-2, MUC2, napsin A, and cytokeratin 20. Collectively, the diagnosis of the tumor was primary mucinous adenocarcinoma of the thymus. We propose that the mucinous subtype should be recognized as one of the histopathological entities of thymic adenocarcinoma.     

Mucinous breast carcinoma with myoepithelial‐like spindle cells

Appearance of spindle cells has been believed as a benign index of breast cytology. But, we have frequently observed the spindle cells in smears from mucinous carcinoma of the breast. Here, we characterized the biochemical nature of the spindle cells, so as to clarify their identity in cytology. Nineteen cases of breast mucinous carcinoma were used for cytological examination. The spindle cells were located at edges of tumor cell nests and in the backgrounds of cytological specimens. Immunohistological examination revealed that the spindle cells exhibited both immunoreactivity against carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA). Immunoreactivity against vimentin, cytokeratin, or alpha‐smooth muscle actin was, however, not observed. The mode of distribution of biochemical markers suggests that the positive cells for anti‐CEA antibody and anti‐EMA antibody are tumor cells compressed by mucin, while the vimentin‐positive cells are fibroblasts. We assert that the presence of spindle cells can be a characteristic feature of mucinous carcinoma of the breast. Discrimination of the spindle cells in mucinous carcinoma from myoepithelial cells and naked bipolar nuclei in benign lesions was established here. It should facilitate precise diagnosis of breast cancer. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Mucinous cystadenocarcinoma of the breast with a basal-like immunophenotype

Mucinous cystadenocarcinoma (MCA) of the breast is extremely rare and was only recently described as a distinct variant of invasive ductal carcinoma of the breast. A case of MCA is reported in a 41-year-old woman. Mammographic and ultrasonographic examinations showed an irregularly shaped 10.0 × 8.0 × 5.5 cm lesion with patching calcification in the upper outer quadrant of the left breast. The gross examination revealed that the tumor has a well-circumscribed edge with a gelatinous cut surface and hemorrhage and necrosis were also noticed in the mass. Microscopically, the mass resembled mucinous cystic neoplasm of the ovary and pancreas closely, with cystic areas lined by columnar mucinous cells and associated with abundant extracellular and intracellular mucin, which is distinctively different from mucinous carcinoma with typically nests of low grade neoplastic cells floating in the mucin pool. The tumor cells were positive for CK7, CK20 and CDX2 were negative and displayed a typical immunophenotype of basal-like breast cancer (ER, PR, HER2 were negative, CK5/6 and EGFR were positive). Metastatic carcinoma was identified in three of 14 axillary lymph nodes. We describe here a very unusual case of breast MCA with basal-like immunophenotype.     

Histochemical and immunohistochemical characterization of canine mammary mucinous carcinoma

Mucinous carcinoma is a rare mammary tumour, characterized by intracellular and extracellular mucin. It is still uncertain whether the origin of the mucin is epithelial, myoepithelial or fibroblastic. Eleven canine cases originally classified as mucinous carcinomas were reassessed and compared with myoepithelial nests of mixed tumours. All samples were examined (1) histochemically by the periodic acid-Schiff (PAS) and PAS-diastase methods, and with alcian blue (pH 2.5 and pH 1.0), mucicarmine and Grimelius silver stain, and (2) immunohistochemically for cytokeratin 19, vimentin, alpha-actin and chromogranin A. This examination revealed that only five of the 11 tumours were genuine mucinous carcinomas. In these five tumours the mucus-secreting cells showed cytoplasmic cytokeratin 19 positivity; the mucus showed PAS-diastase and mucicarmine positivity, and alcianophilia which was stronger at pH 2.5 than at 1.0. The remaining six cases were re-classified as mixed tumours because both mucus and mucus-producing cells shared the following similarities with myoepithelial nests of mixed tumours: vimentin and alpha-actin cytoplasmic positivity, PAS negativity, alcianophilia both at pH 2.5 and 1.0, and mucicarmine positivity.     

肾脏黏液性管状和梭形细胞癌临床病理学观察

目的 探讨肾脏黏液性管状和梭形细胞癌的临床病理学特征、免疫表型及鉴别诊断。方法 应用常规病理、免疫组化方法观察1例肾脏黏液性管状和梭形细胞癌并复习相关文献。结果 肿物与周围肾组织分界清楚，组织学特点是排列呈管状的上皮样细胞，片状的梭形细胞和黏液性间质，无明显核的异型性，缺乏坏死。免疫组化：CK、EMA、vimentin阳性，SMA、desmin、S-100蛋白、HMB45等阴性。结论 肾脏黏液性管状和梭形细胞癌是WHO新确定的一类罕见的低度恶性肾上皮性肿瘤，预后较好，要与后肾腺瘤、肉瘤样癌和集合管癌等疾病相鉴别。     

Bronchioloalveolar carcinoma of mixed mucinous and nonmucinous type: immunohistochemical studies and mutation analysis of the p53 gene

Bronchioloalveolar carcinoma of mixed mucinous and nonmucinous type fulfilling the 1999 WHO criteria is rare. Here, we report a case of this type of tumor determined entirely by histological examinations. A 57-year-old man was incidentally found to have a demarcated 3cm mass in his lower lobe of the right lung. The tumor was composed of tall columnar cells containing cytoplasmic mucins, cuboidal cells without mucins, and intermediate cell types with lepidic growth patterns. Tumor cells were distributed within a region of 2cm in diameter, and no stromal, vascular, or pleural invasion was observed. Immunohistochemically, both the mucinous and nonmucinous components were positive for cytokeratin 7, TTF-1, and E-cadherin, and negative for cytokeratin 20, consistent with the results for nonmucinous bronchioloalveolar carcinoma. No mutations were detected in exons 5-8 of the p53 gene. The present tumor was composed mainly of morphologically mucinous bronchioloalveolar carcinoma, but presented different immunohistochemical profiles of ordinary mucinous bronchioloalveolar carcinoma. This case suggests that the mucinous component in bronchioloalveolar carcinoma of mixed mucinous and nonmucinous type has characters dissimilar to conventional mucinous bronchioloalveolar carcinoma, and is probably derived from the nonmucinous component.     

Breast mucoepidermoid carcinoma: a case report and review of literature

Breast mucoepidermoid carcinoma (MEC) is clinically rare, with an estimated incidence of 0.2-0.3% of all primary breast tumors. To date, only 41 cases have been reported in the literature. Herein, we present a case of breast MEC diagnosed at our hospital. The clinicopathologic features were preliminarily discussed by reviewing the literature. A 42-year-old Chinese woman presented with a lump in her right breast that was detected approximately three months prior. A microscopic examination showed that the breast MEC was composed of different proportions of mucinous cells, intermediate cells, and epidermoid cells. Most mucinous cells were positive for cytokeratin 7, while the epidermoid and intermediate cells were positive for p63 and cytokeratin 5/6. All tumor cells were negative for other myoepithelial markers, such as calponin. Tumor cells did not express estrogen, progesterone, or the HER-2/neu protein. After the patient underwent mastectomy, she was diagnosed with a low-grade mucoepidermoid carcinoma based on the clinical, histologic, and immuno-phenotypic characteristics. Our findings provide further insight into the pathologic mechanism of MEC, as correct diagnosis is essential for patient management.     

Metaplastic carcinoma with extensive chondroid differentiation in the breast (chondroid carcinoma)

Metaplastic breast carcinoma is very rare, and metaplastic carcinoma with chondroid differentiation is even rarer. Here, we report a case of metaplastic carcinoma with extensive chondroid differentiation mimicking chondrosarcoma that was challenging to diagnose. The tumor was characterized by an abundant chondromyxoid matrix. The definitive area of classic invasive ductal carcinoma was minimal. The peripheral portion of the tumor showed increased cellularity with pleomorphism and definitive invasive growth. Tumor cells in the chondrosarcomatous areas were diffusely immunoreactive for S-100 protein, patchy positive for cytokeratin, but negative for epithelial membrane antigen (EMA). Tumor cells in carcinomatous areas were diffusely positive for cytokeratin, S-100 protein, and patchy positive for EMA. In both areas, tumor cells were negative for smooth muscle actin (SMA) and CD34, while oncoprotein p53 was overexpressed. When pathologists encounter breast tumors with chondroid differentiation, careful sampling and immunohistochemistry for cytokeratin and SMA are most helpful to differentiate metaplastic carcinoma from malignant phyllodes tumor and malignant adenomyoepithelioma.     

Mucinous cystadenocarcinoma of the breast coexisting with infiltrating ductal carcinoma

A recently described and rare variant of breast carcinoma, mucinous cystadenocarcinoma (MCA), is reported in a 65-year-old post-menopausal woman. She presented with a gradually enlarged breast tumor. A well-circumscribed tumor measuring about 3 cm in diameter was noted in the mammographic and ultrasonographic examinations. The mammographic and ultrasonographic findings were indistinguishable from more common mucinous carcinoma (colloid carcinoma) of the breast. The gross appearance of the tumor was well-defined and cystic, consisting of abundant transparent to bloody mucin, as well as whitish solid parts. Microscopically, the tumor was characterized by abundant extracellular and intracellular mucin. It looked like a mucinous cystic neoplasm of the ovary and pancreas. Particularly, few microscopic foci of ordinary intermediate-grade infiltrating ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS) were observed around the main lesion in this case. A transition from ordinary DCIS to MCA in situ was found. It might indicate MCA derives from a metaplasia process of ordinary DCIS. MCA can be easily differentiated from mucinous carcinoma by quite different histologic and immunohistochemical findings. According to the previously reported and present cases, MCA of the breast more commonly affects elderly women and has a relatively favorable prognosis.     

Mucin production in medullary carcinoma of the thyroid

Mucin production in medullary carcinoma of the thyroid is rarely mentioned in the literature. We studied 36 cases of medullary carcinoma; 32 lesions were sporadic and four were genetic variants. In 15 cases (42%), mucin production was demonstrated by histochemical means. In six cases (17%), the mucin was only extracellular; in three (8%), it was mostly extracellular, but with foci of intracellular deposits; and in six cases (17%), it was equally extracellular and intracellular. Mucin secretion could be demonstrated in both the primary thyroid tumor and the nodal metastases. No consistent correlation could be demonstrated between the histologic pattern, the staining properties of the tumor cells, and the sporadic or genetic occurrence of the tumor. Mucin was more frequently identified in medullary carcinomas (42%) than in other carcinomas (9.1%) of the thyroid gland. As mucin can be identified in approximately half of the medullary carcinomas, this primary thyroid lesion should be considered a possible source for a cervical node containing mucin positive carcinoma cells.     

Mucinous carcinoma of the breast with neuroendocrine differentiation

A case of mucinous carcinoma of the breast with neuroendocrine differentiation in an 89-year-old woman is presented. The patient presented with a rapidly growing right breast mass, which she had had for 2-3 years. The tumor, 15 x 8 x 5 cm, was located mainly in the upper outer quadrant. Light microscopy revealed a pure mucinous carcinoma of type B. Neuroendocrine differentiation was demonstrated by Grimelius stain and chromogranin A, as well as the presence of neurosecretory granules. The breast cancer cells were of luminal origin and had dedifferentiated to attain neuroendocrine properties.     

Composite type of breast carcinoma with endocrine differentiation: a cytological and immunohistochemical study

We describe a case of breast carcinoma with endocrine differentiation containing a mixture of three different histological features that occurred in a 71-year-old woman. Histologically, the tumor was predominantly intraductal, but slightly invasive. In the intraductal lesion, the tumor consisted mainly of ovoid to round cells with a modest to abundant amount of granular eosinophilic cytoplasm or intracytoplasmic mucin (mucin-producing carcinoma in situ ). It also consisted, in part, of plump spindle cells with scant cytoplasm that contained argyrophilic granules in a trabecular pattern or an arrangement of perivascular pseudorosettes (atypical carcinoid tumor like-features). Mucous lake and tumor cells floating in mucin were seen in the invasive lesion (mucinous carcinoma). Immunohistochemical staining revealed endocrine differentiation of the tumor cells of both intraductal and invasive lesions. These findings suggest that the different histological features derived from pluripotent cells upon endocrine differentiation, and that endocrine differentiation of the tumor cells had already occurred at an earlier stage of carcinogenesis, prior to the appearance of the mucinous carcinoma. Cytologically, plasmacytoid tumor cells appeared in loosely cohesive clusters or as sparsely single cells in a background of a mucinous substance.     

Pigmented adenoid cystic carcinoma of the ear skin arising from the epidermis: a case report with immunohistochemical studies

Adenoid cystic carcinoma (ACC) in the skin is very rare; only about 60 cases have been reported. Herein presented is a case of pigmented ACC arising from epidermis of the ear skin. An 85-year-old man presented black tumor of the right ear. Dermatologists' diagnosis was basal cell carcinoma (BCC). Large biopsy was obtained. The biopsy showed proliferation of atypical basaloid cells arranged in a cribriform pattern. The tumor cells were continuous with epidermis, as if it arose from the epidermis. Focal areas show melanin deposition in the tumor cells. Mucin stains showed that the tumor cells and tubular lumens contained acidic mucin. Immunohistochemically, the tumor cells were positive for cytokeratin (CK) AE1/3, CK34BE12, CK5/6, CK7, CK14, p63, alpha-smooth muscle actin (ASMA), S100 protein, p53, Ki-67 (labeling 85%), KIT, PDGFRA and CD56. The tumor cells were negative for CK CAM5.2, CK8, CK18, CK19, CK20, EMA, desmin, CEA, HMB45, CD10, CD34, neuron-specific enolase, chromogranin, synaptophysin, CDX2, MUC1, MUC2, MUC5AC and MUC6. HMB-positive and S100-positive melanocytes were seen in a very few areas. Since characteristic cribriform pattern was recognized in the tumor and the tumor showed epithelial markers, myoepithelial markers (CD14, p63, ASMA, S100 protein) and KIT, the pathological diagnosis of ACC was made. No distant and lymph node metastasis is now seen. The patient will be treated by complete resection. The present cutaneous ACC was unique in that the ACC arose from the epidermis, had melanin pigment, and occurred in ear skin.     

Gastric undifferentiated carcinoma with diffuse c-kit overexpression and focal neuroendocrine differentiation

A case of gastric undifferentiated carcinoma with diffuse c-kit overexpression and focal neuroendocrine differentiation is described. A 76-year-old man presented appetite loss for 1 month. Gastric endoscopy showed an exophytic huge nodular mass with central ulceration at the gastric prepylorus. Distal gastrectomy was performed with lymph node dissection. Histology indicated anaplastic medium- to large-sized round tumor cells in discohesive sheets. Adenocarcinomatous areas forming tubular glands or with intracytoplasmic mucin on PAS and Alcian-blue staining were not found in any sections. Immunohistochemistry showed that the tumor cells were diffusely positive for cytokeratin, vimentin, c-kit and focally positive for chromogranin A and synaptophysin.     

Neovascularization in mucinous ductal carcinoma in situ suggests an alternative pathway for invasion

Aims: Ductal carcinoma in situ (DCIS) associated with invasive mucinous carcinoma (IMC) has not been well characterized. The aim was to characterize mucinous DCIS (mDCIS) of the breast and to describe, to our knowledge for the first time, neovascularization in mucin. Methods and results: The pathology reports and slides were reviewed from 44 patients treated between 2003 and 2006 at The University of Texas M. D. Anderson Cancer Center, whose diagnosis fulfilled the criteria of IMC or DCIS with mucin production. The patients, all female, had a mean age of 62 years. DCIS was present in 93% of cases and the predominant histological types were solid, cribriform and micropapillary. The DCIS was grade 1 in 12 of 41 cases (29.3%), grade 2 in 25 of 41 cases (61%) and grade 3 in four of 41 cases (9.8%). Mucin was seen in the lumen of the ducts involved by DCIS in 88% of cases, mucin and vessels in 63.4% of cases and neither mucin nor vessels in 12.2%. The DCIS was vascular endothelial growth factor‐positive, platelet‐derived growth factor receptor‐beta‐positive and CDX‐2‐negative (100%). Occasional luminal cells within the DCIS were immunopositive for CD68. Conclusions: A significant number of mDCIS showed neovascularization in intraluminal mucin. When identified on core needle biopsy, the presence of vascularized mucin should not be used alone to discriminate between invasive and in situ carcinoma. A hypothesis proposed for the source of recruitment of vessels in the mucin is that mucin can promote neovascularization and that tumour cells invade not into the adjacent fibroconnective tissue, but rather into the mucinous, richly vascularized stroma that they have induced. Alternatively, it is possible that both cells and their secretory product invade together. To our knowledge, this is the first study to characterize neovascularization within the mucinous component of DCIS associated with and without IMC.     

Gastric-type mucinous adenocarcinoma of the uterine cervix with neoadjuvant therapy mimicking clear cell carcinoma

Gastric-type mucinous adenocarcinoma, an uncommon subtype of cervical carcinoma, is characterized by a distinct morphology and immunophenotype. Herein, we report a case of a 71-year-old woman who received neoadjuvant radiotherapy and chemotherapy after cervical biopsy revealed moderately differentiated invasive endocervical adenocarcinoma. Subsequently, the outside patient underwent radical hysterectomy with bilateral salpingo-oophorectomy. The post-neoadjuvant therapy hysterectomy specimen showed tumor cells with clear cytoplasm, hyperchromatic nuclei with irregular contours, which mimicked clear cell carcinoma. However, immunohistochemical staining showed that these tumor cells were positive for carcinoembryonic antigen, cytokeratin 7 (diffuse), and cytokeratin 20 (patchy), After review of the pretreatment cervical biopsy specimen, the tumor was favored to represent a gastric-type mucinous adenocarcinoma of the cervix. Pathologists should be aware of this rare tumor and its post-neoadjuvant therapy morphologic changes, which can make diagnosis more challenging.     

Mucinous breast carcinoma and mixed mucinous-infiltrating ductal carcinoma: a comparative cytologic study

In its pure form, mucinous breast carcinoma (MC) has a much better prognosis than infiltrating ductal carcinoma (IDC). Mixed MC-IDC has the prognosis of IDC. We compared the fine-needle aspiration (FNA) cytology and histology of nine cases of pure MC with 13 cases of mixed MC-IDC. While typical of pure MC, abundant mucin (3+/3+) was noted in smears from three cases of mixed tumor and is thus necessary but not sufficient for a diagnosis of pure MC. Cellular pleomorphism has been said not to be a feature of MC; however, we found occasional large cells markedly different from the typical small uniform cells of MC in four pure and seven mixed tumors. Cytologic features indicative of a mixed tumor include one or more smears totally without mucin, scantly amounts of mucin, or necrosis. A combination of features indicative of pure mucinous carcinoma in FNA included abundant mucin on all smears, no pleomorphism, and no necrosis. Many cases will have smear patterns that are not typical of either profile and should probably be designated as carcinoma with a mucinous component.     

Pseudoangiosarcomatous features in medullary thyroid carcinoma spindle-cell variant. Report of a case studied by FNA and immunohistochemistry

We report a case of medullary thyroid carcinoma (MTC), spindle cell variant, which exhibited striking histological pseudovascular clefts and abortive lumina, closely mimicking an angiosarcoma. The patient is a 72-yr-old-man who presented facial rash and a solid nodule in the right lobe of the thyroid gland. The fine-needle aspiration (FNA) showed bloody background containing loosely groups of fusiform and plasmocytoid cells with coarse chromatin and eosinophilic granular cytoplasms. Microscopically, the tumor exhibited spindle-cell pattern intermingled with a striking angiosarcoma-like pattern characterized by the presence of abortive lumen and clefts containing erythrocytes. Dense hyaline extracellular amyloid was present. The tumor cells were strongly positive for cytokeratin, chromogranine-A, synaptophysine, serotonin, calcitonin, and CEA. TTF-1 was weakly positive. Stains for CD34 and CD31 were negative. This case illustrates that the spindle cell variant of MTC may exhibit an infrequent angiosarcoma-like appearance which may be misdiagnosed as angiosarcoma.