Primary cutaneous solitary fibrous tumor with entrapped eccrine components

First described in the pleura, solitary fibrous tumor (SFT) was subsequently reported in a variety of organ systems. Compared to other anatomic sites, primary cutaneous and superficial SFTs are relatively rare. Although several histopathologic variants of cutaneous and superficial SFT have been described, a primary cutaneous SFT harboring glandular components has not hitherto been documented in the literature. The current case report describes a spindle cell neoplasm of the right finger in a female patient with characteristic morphologic and immunohistochemical features of a SFT. Unexpectedly, various glandular and ductal components were identified in the SFT. A few hyperplastic lobules of sweat glands demonstrating similar morphology as the intratumoral glandular components and composed of secretory coils displaying mucinous metaplasia and ducts were detected in the attached subcutaneous tissue, suggestive of an inductive or obstructive effect of the SFT on the eccrine units. The intratumoral glands and ducts were judged to represent entrapped benign eccrine components from the attached subcutaneous tissue. Since this variant of SFT with entrapped eccrine components could mimic many biphasic epithelial and stromal tumors, pathologists should be aware of this unusual variant of SFT to avoid potential erroneous diagnosis, particularly mistaken confusion with a biphasic synovial sarcoma.     

Primary cutaneous adenomyoepithelioma

An 83-year-old Caucasian woman presented to her dermatologist with a 5-cm subcutaneous tumor on her right thigh. The lesion had been present for many years, but had recently enlarged. Incisional biopsy showed a multinodular tumor composed of variably sized glands comprised of a luminal layer of epithelial cells surrounded by one or more layers of myoepithelial cells. The histopathologic features resembled those of adenomyoepithelioma, an uncommon neoplasm usually encountered within the breast. Primary cutaneous adenomyoepithelioma is very rare yet shares histopathologic features with common cutaneous lesions such as spiradenomas and benign mixed tumors (chondroid syringomas). Primary cutaneous adenomyoepithelioma is part of the spectrum of epithelial-myoepithelial tumors that includes benign mixed tumor, myoepithelioma and myoepithelial carcinoma. This rare tumor may mimic malignant lesions including metastatic adenocarcinoma. Like its breast counterpart, primary cutaneous adenomyoepithelioma should probably be regarded as a neoplasm of borderline malignant potential.     

Microcystic adnexal carcinoma: a case report with immunohistochemical and electron microscopical examinations.

Microcystic adnexal carcinoma (MAC) is an unusual cutaneous neoplasm comprised of pilar and sweat duct structures. We report here a 66-year-old Japanese woman with MAC on her left nasolabial fold with more prominent calcified keratinous cysts than ductal differentiated structures which stained positively for carcinoembryonic antigen (CEA). The clinical appearance and statistical characteristics of MAC are reported to be different from those of other adnexal tumors. Desmoplastic trichoepithelioma (DTE) is the most difficult tumor to differentiate from MAC, unless positive reactivity for CEA in differentiated ductal structures in MAC can be demonstrated. We compare the differences between the clinical, histological, immunohistochemical, and electron microscopical features of DTE and MAC. It seems probable that these differences could be explained by biological differences in the characteristics of the cells from which these tumors originate, hair follicle cells and eccrine sweat cells, respectively.     

Lymphoepithelioma-like carcinoma of the skin with spindle cell differentiation

BACKGROUND: Primary cutaneous LELC is a cutaneous neoplasm with histopathologic features identical to those seen in the undifferentiated subtype of nasopharyngeal carcinoma. It is extremely rare, with only approximately 30 cases reported in the literature. METHODS: We report a case of primary cutaneous LELC arising on the forehead of a 72 year-old male in which a proportion of the neoplastic cells demonstrated distinctive spindle cell morphology. RESULTS: Microscopic examination showed a dense lymphoplasmacytic infiltrate admixed with large spindle-shaped cells with vesicular nuclei, prominent nucleoli, and frequent mitotic figures. These cells were negative for an extensive panel of immunohistochemical markers and positive only for broad-spectrum cytokeratins and epithelial membrane antigen. There was no connection between the tumor and the epidermis and no epidermal dysplasia. In situ hybridization for Epstein-Barr virus was negative. CONCLUSIONS: The spindle cell differentiation in this case is unusual and suggests that in some cases the differential diagnosis of cutaneous spindle cell neoplasms might include primary cutaneous LELC.     

Clear cell syringoid eccrine carcinoma

A case of syringoid eccrine carcinoma (SEC) is reported. The tumor was mainly formed by clear cells laden with glycogen. This feature, rarely found in syringoma, had not previously been reported in SEC. The authors assume that SEC is an infiltrating and locally destructive but not metastasizing neoplasm. They propose that SEC is a clinicopathologic entity with a histopathologic spectrum from the more differentiated syringomatoid ones to so-called primary cutaneous adenoid cystic carcinoma. A possible nexus between the more syringomatoid cases and the sclerosing sweat duct (syringomatous) carcinoma is also discussed.     

Cutaneous myoepithelial neoplasms: clinicopathologic and immunohistochemical study of 20 cases suggesting a continuous spectrum ranging from benign mixed tumor of the skin to cutaneous myoepithelioma and myoepithelial carcinoma

BACKGROUND: Myoepithelial neoplasms, both benign and malignant, are rare but well-established clinicopathologic entities in the salivary glands, the breast, and the lung. Despite similarities between cutaneous sweat glands and glandular structures in the above-mentioned organs as well as the presence of regular myoepithelial cells around cutaneous eccrine/apocrine glands, the concept of cutaneous myoepithelial neoplasms is still debatable and not commonly accepted. METHODS: Twenty cutaneous myoepithelial neoplasms have been studied histologically and immunohistochemically. RESULTS: Nine neoplasms showed features of benign mixed tumor of the skin (chondroid syringoma) (five females and four males, age range 19-65 years, all cases arose in the head and neck region). Two cases represented the eccrine and seven the apocrine subtype. Interestingly, in three cases of the apocrine subtype, solid areas composed predominantly of myoepithelial cells were detected; these neoplasms were designated as benign mixed tumors with prominent myoepithelial cells. Nine cutaneous neoplasms were composed of spindled, epithelioid, and plasmocytoid cells without ductal differentiation and immunohistochemically stained variably positive for vimentin, epithelial and myogenic markers, S-100 protein, calponin, and glial fibrillary acidic protein (four females and five males, age range 3-71 years, four cases arose in the head and neck region and one case each on the finger, the thigh, the lower leg, the foot, and the breast, respectively); these neoplasms were designated as cutaneous myoepitheliomas. Two morphologically malignant neoplasms with cytologic and immunohistochemical features of myoepithelial cells arose on the face of a 70-year-old female and a 79-year-old male patient; these neoplasms were designated as malignant cutaneous myoepitheliomas (cutaneous myoepithelial carcinomas). CONCLUSIONS: The study suggests a continuous spectrum of cutaneous myoepithelial neoplasms ranging from benign mixed tumor of the skin to cutaneous myoepithelioma and cutaneous myoepithelial carcinoma. Further studies with extended follow-up information are necessary to establish prognostic factors.     

Lupus erythematosus with exclusive involvement of the acrosyringia

Cutaneous lesions of lupus erythematosus (LE) show a broad spectrum of clinicopathologic features. Histopathologically, besides typical patterns such as interface dermatitis, perivascular lymphocytic infiltrate and dermal mucin deposits, an involvement of the eccrine structures, especially the acrosyringium, may be observed. We describe the case of a 21-year-old woman with a 4-year history of systemic LE, who presented with a 'butterfly' rash over the cheeks as well as erythematous macules on the arms and décolleté. Biopsy from one lesion on the arm revealed interface changes, necrotic keratinocytes and exocytosis of lymphocytes restricted only to the regions of the acrosyringia. The epidermis between affected acrosyringia was normal with no hints of interface dermatitis. The eccrine glands and coils were not affected. In the dermis there were only sparse inflammatory infiltrates. Differential diagnoses such as erythema multiforme, drug eruption and lichen planus could be ruled out because of histopathologic features and clinical presentation. This is an example of a peculiar histopathological variant of cutaneous LE, characterized by exclusive involvement of the acrosyringia. The histopathologic features represent a pitfall in the diagnosis and can be correctly interpreted only upon correlation with clinical data.     

Melanocytic matricoma with melanocytic atypia: report of a unique case and review of the literature

Melanocytic matricoma is a rare cutaneous neoplasm of presumed anagen hair follicle origin with approximately 10 reported cases in the literature. Melanocytic matricomas are clinically and histopathologically distinct cutaneous nodular proliferations of matrical and supramatrical cells admixed with dendritic melanocytes, which typically occur in the sun-exposed areas of elderly patients. We report a new case with additional histopathologic features not previously described. An 82-year-old white man presented with an exophytic papule of the ear clinically suspicious for basal cell carcinoma. Histopathologic examination demonstrated a polypoid neoplasm consisting of an admixture of matrical and shadow cells with numerous interspersed dendritic and epithelioid melanocytes arranged singly and in large expansile nests. An unusual feature in this case included prominent melanocytic proliferation with associated nuclear atypia and increased mitotic activity. Although atypical and malignant melanocytic colonization has been reported in basal cell carcinomas and squamoproliferative lesions, to our knowledge, it has not been previously described in melanocytic matricomas. The biologic significance of atypical melanocytic proliferations within melanocytic matricomas is uncertain and requires further study of additional cases and long-term follow-up.     

Cutaneous spindled follicle center cell lymphoma with abundant mucin: A diagnostic pitfall

Primary cutaneous follicle center cell lymphoma is the most prevalent type of primary cutaneous B-cell lymphoma and usually portends a favorable prognosis. Typically, the diagnosis can be rendered based on characteristic histopathologic features and immunohistochemical profile. Rarely, a diagnostically challenging variant with a predominant spindle morphology mimicking other malignant spindle cell neoplasms may be encountered. Even more unusual is the presence of a prominent myxoid stroma in this rare sarcomatoid variant of follicle center cell lymphoma. Herein, we present a case of a 52-year-old man with a slowly enlarging cyst-like lesion on the chin with histopathologic examination revealing a malignant, predominantly spindled neoplasm within an abundant myxoid stroma. Following a broad panel of immunohistochemical stains, the strong positive staining of the spindle cells for LCA (CD45), CD20, and Bcl-6 confirmed the diagnosis of follicle center cell lymphoma. We present this distinctive rare subtype of cutaneous follicle center cell lymphoma to increase awareness of this variant and to discuss challenging histopathologic mimics to consider while highlighting the utility of immunohistochemistry stains to avoid misdiagnosis.     

Low-grade fibromyxoid sarcoma: case report and immunohistochemical study

A case is presented of low-grade fibromyxoid sarcoma involving the arm of a 52-year-olcl man. Low-grade fibromyxoid sarcoma is a recently described neoplasm of the deep and subcutaneous soft tissue which demonstrates a spectrum of histologic images. The current case demonstrated the typical patterns of intermixed, sweeping bands of fibrous and myxoid tissue, homogeneous foci of fibrous and myxoid tissue, focal areas of storiforming, and concentric perivascular cuffs of slender spindle cells, all lacking the nuclear anaplasia, mitotic activity, and necrosis generally associated with sarcomas. Immunohistochemical analysis performed on paraffin-embedded sections demonstrated strong labeling of the tumor cells by anti-CD34 antibody, moderate labeling for vimientin, and rare, focal positivity for muscle-specific actin. Tumor cells were negative for markers of epithelial, muscular, neural, histiocytic, melanocytic, and vascular differentiation. The constellation of histopathologic features described in this arid previous reports is characteristic of low-grade fibromyxoid sarcoma. Based on this case, it appears that the immunohistochemical features of low-grade fibromyxoid sarcoma can help to exclude many cutaneous and deep soft tissue tumors from the differential diagnosis. The findings support the interpretation that the neoplasm is essentially fibroblastic in nature.     

Cutaneous apocrine mixed tumor with intravascular tumor deposits: a diagnostic pitfall

Apocrine mixed tumor of the skin is a benign adnexal neoplasm usually posing no diagnostic problem for a histopathologist. The purpose of our investigation is to present a small series of 4 benign cutaneous apocrine mixed tumors of the skin that contained small foci of intravascular tumor deposits, a feature not previously described, to the best of our knowledge. The 4 lesions were identified retrospectively after a review of 312 apocrine mixed tumors and 51 eccrine mixed tumors in the collective files of the authors. In all cases, this feature was originally overlooked. The patients were 3 men and 1 woman, ranging in age at diagnosis from 29 to 66 years. Locations included nose (2), forehead (1), and the fifth toe (1). Histopathologically, all 4 neoplasms demonstrated typical features of a benign apocrine mixed tumor; 2 cases were classified as hyaline cell-rich tumors. In all cases, there were either blood or lymphatic vessels containing small intraluminal collections of neoplastic cells, which had the appearances of hyaline cells and immunohistochemically expressed cytokeratins and were partly immunoreactive for S-100 protein and calponin, thus indicating the myoepithelial phenotype. The intravascular location of the neoplastic cells was confirmed by CD31 staining. The nature of the vessels (lymphatics vs. blood vessels) was supported by staining for alpha smooth muscle actin, which stained pericytes in blood vessels. Lymphatic vessels were also stained for D2-40. No eccrine mixed tumor manifested intravascular tumor deposits. Follow-up of the patients revealed no recurrences or metastasis (range: 2-21 years). It is concluded that occurrence of intravascular involvement in benign apocrine mixed tumor of the skin is rare (approximately 1%-2%). This feature is discrete and is easy to overlook. At present, its significance is not completely clear. Until proved otherwise in future, we suggest to consider intravascular deposits in cutaneous apocrine mixed tumors as an innocuous phenomenon.     

Spiradenocylindrocarcinoma: a malignant hybrid tumor

BACKGROUND: Eccrine spiradenomas and cylindromas are benign, slowly growing, cutaneous adnexal neoplasms, recently hypothesized to arise from a common pluripotential cell; malignant variants are rare. We found 48 cases of malignant spiradenomas and 33 cases of malignant cylindromas reported in the English literature. Benign tumors demonstrating both spiradenomatous and cylindromatous features have been infrequently reported. Recent immunohistochemical studies of these two tumors have provided compelling evidence that these two tumors may merely represent a single tumor type with a spectrum of histological features. CASE REPORT: We describe two cases of a malignant variant of this rare hybrid tumor occurring in a 62-year-old male and a 72-year-old female. CONCLUSION: We propose the term 'spiradenocylindrocarcinoma' to describe malignant tumors with features of both a spiradenoma and a cylindroma. In conjunction with histological features of malignancy, p53 and Ki-67 immunohistochemical staining may provide helpful clues in determining the malignant potential of this tumor. Further studies are needed to clarify the biologic behavior of such lesions.     

Lipomatous mixed tumor of the skin

An unusual tumor of the neck in a 56-year-old female is reported. The tumor was composed of tubules and small cords of epithelial cells dispersed in the fibromyxoid and adipose stroma. At the periphery, the tumor was not encapsulated and its border was intermingled with the subcutaneous fat. Lack of decapitation secretion and the absence of long tubules suggested an eccrine origin; however, in some of the tumor areas, the cells showed brightly eosinophilic copious cytoplasm that may indicate an apocrine differentiation. As an area of chondroid metaplasia was identified, the diagnosis of a mixed tumor was rendered. This unusual type of skin adnexal neoplasm with unique relation of the epithelial component to the surrounding adipose tissue requires differentiation with the primary cutaneous and metastatic carcinomas.     

Cutaneous malignant mixed tumor. Report of a case and review of the literature

We describe an unusual malignant cutaneous neoplasm having a biphasic growth pattern and apparently arising in a mixed tumor. A lymph node metastasis was similar histologically to the primary lesion, exhibiting both carcinomatous differentiation and areas that appeared sarcomatous. Immunohistochemical stains showed selective staining for high molecular weight keratin in carcinomatous areas and for vimentin in areas having a sarcomatous appearance. The literature of cutaneous malignant mixed tumor is reviewed and possible explanations for the unusual morphology and immunohistochemical staining pattern are discussed.     

Basal cell carcinoma with prominent central palisading of epithelial cells mimicking schwannoma

Basal cell carcinoma (BCC), the most common malignant neoplasm of skin, may show a wide spectrum of histologic appearances. The presence of peripheral palisades is a very characteristic feature of BCC but, to our knowledge, central nuclear palisading has never been described. We report two cases of BCC exhibiting striking central nuclear palisading with Verocaylike bodies, in a pattern reminiscent of schwannoma. Peripheral palisades and clefts were also present in most tumor nodules and lobules, giving the neoplasms the overall configuration of otherwise typical solid BCC. In addition, foci of conventional BCC could be found adjacent, and in transition, to schwannoid areas. The immunohistochemical study showed strong reactivity for keratins (AE1 and AE3) in tumor cells, whereas no immunostaining for S-100 or muscle-specific actin was found. This previously undescribed histological feature of BCC should lead us to include BCC in the list of tumors to be considered in the differential diagnosis of a cutaneous neoplasm with schwannoid features.     

Cylindroma expresses immunohistochemical markers linking it to eccrine coil

Nerve growth factor, S-100 protein, CD44, and CD34 have unique expressions in or surrounding eccrine coil hut are not found in eccrine duct or apoerine gland. We studied 15 cases of cutaneous cylindroma to see if these antigens are found in this neoplasm. All were found in cylindroma to varying degrees. These results link the histogenesis of cylindroma to the eccrine coil. A unique feature of cylindroma is the large number of prominent dendritic cells most likely representing Langerhans cells that permeate the tumor aggregates.     

Incidentally discovered distant cutaneous metastasis of sacral chordoma: a case with variation in S100 protein expression (compared to the primary tumor) and review of the literature

Chordomas represent rare malignant primary bone tumors most often occurring in the sacral area. These tumors uncommonly involve the skin and often follow a progressive course with multiple recurrences, metastases and eventual death. Reports of cutaneous metastases from chordoma are very rare. The immunohistochemical staining characteristics of these cutaneous metastases with comparison to the primary tumors are similarly rarely addressed in the literature. We report a rare case of incidentally discovered, small, solitary distant cutaneous metastasis of sacral chordoma that developed on the right upper back of a 44-year-old man with a history of multiple completely excised melanomas who had also been previously diagnosed with chordoma involving the sacrum 12 years earlier. We describe its pathologic features with comparison to the primary tumor and briefly review the literature. Immunohistochemically, the cutaneous metastasis and primary tumor both stained positively for pancytokeratin and vimentin, as expected. However, the cutaneous metastasis unexpectedly lacked S100 protein expression, whereas the primary tumor was S100 positive. This phenomenon has only been documented in one other case report. We demonstrate that late, incidentally discovered cutaneous metastasis with unexpected immunohistochemical staining features rarely occur and can present a diagnostic challenge.     

Cutaneous histopathologic, immunohistochemical, and clinical manifestations in patients with hemophagocytic syndrome. Military Medical Consortium for Applied Retroviral Research (MMCARR).

BACKGROUND AND DESIGN--The hemophagocytic syndrome (HPS) is characterized by fever, wasting, generalized lymphadenopathy, hepatosplenomegaly, and pancytopenia, often with associated coagulopathy. The most common cutaneous manifestations are panniculitis and purpura. Cytophagic histiocytic panniculitis fits within the spectrum of HPS, and the most consistent histopathologic feature in HPS is a proliferation of mature histiocytes that exhibit prominent erythrophagocytosis and cytophagocytosis. The clinical spectrum, the underlying causes, and the histopathologic features found in HPS are broad. The characteristic phagocytic histiocytes seen in HPS have been confused with malignant histiocytes in the past, but are now known to be reactive. The clinical findings, histologic, and immunohistochemical features of 10 cases of HPS with cutaneous lesions were reviewed. Immunohistochemical markers included KP-1, beta F-1, UCHL-1, L-26, MAC-387, factor XIIIa, and S100 protein. RESULTS--The HPS was associated with T-cell lymphoma and/or viral infection. Most biopsy specimens showed edema and hemorrhage with a lymphohistiocytic infiltrate and prominent histiocytic cells showing erythrophagocytosis and, in some cases, cytophagocytosis. The histiocytic cells showed positive reactions for KP-1 and negative reactions for the lymphoid markers. In all cases the lymphoid cells showed a mixed pattern with most cells positive for beta F-1 and UCHL-1, and a small percentage positive for L-26. CONCLUSION--In HPS, the prominent phagocytic histiocytes are reactive and are stimulated by T-cell lymphocytes, either neoplastic or in response to viral infection. Many of the findings in the HPS may also be due directly or indirectly to cytokines produced by proliferating T-cell lymphocytes and/or reactive phagocytic histiocytes.     

Características dermatoscópicas del poroma ecrino

Eccrine poroma is a benign adnexal neoplasm that clinically may mimic malignant skin tumors such as squamous cell carcinoma and amelanotic melanoma. The dermoscopic features of pigmented and nonpigmented eccrine poroma have recently been described. We present 2 cases of eccrine poroma, with their dermoscopic features. The lesions were characterized by multiple red lacunes and a polymorphous vascular pattern in both cases. Dermoscopy can improve the clinical diagnosis of this benign adnexal skin tumor.