Signet ring cell basal cell carcinoma: a basal cell carcinoma with myoepithelial differentiation

CD56 and smooth muscle actin immunoreactivity in basal cell carcinomas: Are they indicators of differentiation or do they hold a diagnostic use?

BACKGROUND

Basal cell carcinoma (BCC) is the most common cutaneous malignancy and may show various differentiations. The possible pluripotent stem cell lineage of BCCs, whose origins are controversial today, is thought to be the main reason for the different morphologies. The aim of the study is to evaluate the expression of some neuroendocrine and smooth muscle markers of differentiation in BCCs and investigate the relationship between histopathologic subtypes and recurrence.

METHODS

A total of 128 cases diagnosed as BCC in our center were included. Immunohistochemical studies of CD56, synaptophysin, chromogranin-A, smooth muscle actin (SMA), desmin, caldesmon, and Ki67 were applied.

RESULTS

CD56, chromogranin-A, and synaptophysin immunoreactivity were detected in 77.3%, 13.3%, and 0.8% of the cases, respectively. 78.1% showed SMA positivity while no tumor expressed desmin or caldesmon. A correlation between histopathologic recurrence risk groups and CD56 expression was found (p < 0.05).

CONCLUSIONS

CD56 and SMA immunoreactivity is present in the majority of BCCs. However, the available findings do not support neuroendocrine or smooth muscle differentiation. CD56 antigen can be used for prognostic purposes in detecting high recurrence risk tumors. After the investigation of the expression rates of these two antigens in different cutaneous tumors, it may be appropriate to use them for diagnostic purposes in BCCs.

Histomorphological and immunophenotypical spectrum of cutaneous myoepitheliomas: A series of 35 cases

Myoepithelial tumors comprise a group of mesenchymal lesions that show heterogeneous histomorphological features, including dual epithelial, neural, and myoid differentiation. Cutaneous myoepithelioma is a rare neoplasm that is composed primarily of myoepithelial cells and represents one end of a histopathological spectrum of cutaneous myoepithelial neoplasms including chondroid syringoma and myoepithelial carcinoma. These tumors display a wide histopathological spectrum and immunophenotypical profile often showing epithelial and myoepithelial differentiation. In this series, we studied 35 cases of cutaneous myoepitheliomas. Our cases highlighted the broad histopathological range where most cases showed a non-infiltrative and non-encapsulated tumor exclusively located in the dermis and with no subcutaneous involvement. The majority of our cases had a solid growth pattern (syncytial pattern) and the remainder of cases had a multinodular growth pattern. The tumor cells were epithelioid in 23 cases, spindled in eight cases and there was a mixture of epithelioid and spindled cells in four cases. Mitotic figures ranged from 0 to 5 per 10 HPF. By immunohistochemistry epithelial membrane antigen (EMA) was expressed in 59% of cases S100 was positive in 88% of cases, CAM 5.2 was positive in 16% of cases, AE1/AE3 was positive in 44% of cases, p63 was positive in 17% of cases, smooth muscle actin was positive in 38% of cases, desmin was positive in 6% of cases, calponin was positive in 22% of cases, and glial fibrillary acidic protein was positive in 36% of cases. In addition, there were five cases without EMA, keratin, or p63 expression that only showed S100 expression. We describe a large series of cutaneous myoepitheliomas delineating their histomorphological spectrum and immunophenotypical profile. Awareness of some of the unusual histopathological features and the heterogeneous immunohistochemical may pose difficulties for the diagnosis.

Basal cell carcinoma with signet ring cell morphology accumulating the ubiquitinated cytokeratin 5/6

Basal cell carcinoma (BCC) showing signet ring (SR) cell morphology is a very rare variant of BCC. Here, we report BCC with SR cell morphology developed in the right cheek skin of a 79-year-old man. Histopathologic examination showed irregularly shaped islands of basaloid cells with characteristic peripheral palisading. Inside of the cancer islands, many tumour cells showed an enlarged fine granular cytoplasm with the peripherally compressed nuclei, being similar to the SR cell. Immunohistochemical examination revealed dense accumulation of cytokeratin (CK) 5/6 and a faint signal of 34βE12 in SR cells. The reported myoepithelial markers were not detected. Interestingly, ubiquitin, a component of the ubiquitin-proteasome protein degradation system, was co-localised in the SR cells. These suggest, for the first time, that accumulation of the undegraded CK5/6 with ubiquitination results in the SR cell morphology. Our report showed that the aberrant keratin turnover is associated with the SR cell BCC.

Primary cutaneous biphasic sarcomatoid basal cell carcinoma with myoepithelial carcinoma differentiation: A new variant

Isolated cases of basal cell carcinoma (BCC) with partial myoepithelial component have been described. However, myoepithelial differentiation has not been described in sarcomatoid basal cell carcinomas, which usually show features resembling osteosarcoma, chondrosarcoma, or leiomyosarcoma. We report a case of an 87-year-old man with a forehead lesion that histologically showed a minor component of conventional nodular BCC in transition with a major biphasic sarcomatoid growth composed of invasive spindle-cell and epithelial-like components, the latter with a reticular pattern and scattered ductal structures. Both components showed cytological atypia and high mitotic rate (26/10HPF), with atypical mitotic figures. BER-EP4 immunostaining was exclusively found in the nodular BCC component whereas the sarcomatoid component revealed immunostaining for α-smooth muscle actin (SMA), muscle-specific actin (MSA), calponin, and p63 in both epithelial-like and spindle-cell populations. Focal immunoreactivity was observed in the epithelial component for S100 and glial fibrillary acidic protein (GFAP). Furthermore, EWSR1-PBX1 gene fusion was also detected. This is to our knowledge, the first fully documented case of biphasic sarcomatoid BCC with myoepithelial carcinoma differentiation.

Basal Cell Carcinoma with Myoepithelial Differentiation: Case Report and Literature Review

Basal cell carcinoma is the most common skin cancer. Myoepithelial cells are specialized epithelial cells. Basal cell carcinoma with myoepithelial differentiation is a rare tumor. A 71-year-old man with a basal cell carcinoma with myoepithelial differentiation that presented as an asymptomatic red papule of two months duration on his forehead is described. Including the reported patient, this variant of basal cell carcinoma has been described in 16 patients: 11 men and five women. The patients ranged in age at diagnosis from 43 years to 83 years; the median age at diagnosis was 66 years. All of the tumors were located on the face—most were papules or nodules of less than 10 x 10 mm. Their pathology demonstrated two components: one was that of a typical basal cell carcinoma and the other was myoepithelioma-like in which the tumor cells were plasmacytoid or signet ring in appearance and contained abundant eosinophilic cytoplasm or hyaline inclusions or both. The myoepithelial tumor cells had variable immunohistochemical expression that included not only cytokeratin but also actin, glial fibrillary acid protein, S100, and vimentin. The most common clinical impression, prior to biopsy, was a basal cell carcinoma. The pathologic differential diagnosis included cutaneous mixed sweat gland tumor of the skin, myoepithelioma, myoepithelial carcinoma, and tumors that contain a prominent signet ring cell component (such as metastatic gastrointestinal and breast carcinoma, melanoma, plasmacytoid squamous cell carcinoma, and T-cell lymphoma). Mohs micrographic surgical excision, with complete removal of the tumor, was recommended for treatment of the carcinoma.

[Basal cell carcinoma and rare form variants]

Basal cell carcinomas are the most common primary cutaneous malignant neoplasms. The diagnosis of basal cell carcinoma represents a common and routine task for pathologists and dermatopathologists. The aim of this review is the clinical and histopathological presentation of the most common subtypes of basal cell carcinoma. Furthermore, the rare variants of basal cell carcinoma and their differential diagnoses are also discussed.

Basal cell carcinomas showing histological features generally associated with cutaneous adnexal neoplasms

Basal cell carcinoma (BCC) is the commonest malignant neoplasm in humans. Although a histopathological diagnosis of BCC is straightforward in the vast majority of cases, unusual histological variants can present a diagnostic challenge. A small proportion of BCCs show features which are generally associated with cutaneous adnexal neoplasms. Such changes may involve either the epithelium or the stroma and can mislead the pathologist particularly in small biopsies. Despite the growing evidence which speculate that BCC is a primitive follicular tumor, it is unusual to encounter tumors which actually show definitive signs of adnexal differentiation. This review aims to address this somewhat overlooked aspect of a very common tumor and offers practical guidance to distinguish them from adnexal neoplasms which they might mimic.

Signet ring cell melanocytic nevus: report of a case over trichilemmal cyst and review of the literature

Different melanocytic nevi have been reported as being associated with dermal cysts. Signet ring cell melanocytic nevus is a rare variant of melanocytic nevus characterized by cells with signet ring morphology within a common melanocytic nevus. This article describes an exceptional case of melanocytic nevus composed exclusively of signet ring cells over a trichilemmal cyst. Histologically, above the cyst, there was a small, symmetrical and sharply demarcated lesion showing a compound proliferation of small, round, monomorphous cells with signet ring morphology. Immunohistochemically, signet ring cells were negative for cytokeratin AE1/3, leukocyte common antigen, HMB-45, and CD34. Occasionally, isolated signet ring cells were positive for S-100 and melan A. Melanocytic nevus composed of signet ring cells should raise the differential diagnosis with other cutaneous tumors exhibiting signet ring cells. Previous cases of this entity reported in the literature are also reviewed.

Primary cutaneous signet-ring cell melanoma with pseudoglandular features, spindle cells and oncocytoid changes

The authors report a 69-year-old man with a primary nodular malignant melanoma on the shoulder showing unusual histological features. It mostly consisted of markedly neoplastic melanocytes, which exhibited abundant clear cytoplasm compressing the nuclei to the periphery, resulting in a signet-ring appearance. In other areas of the melanoma, there were focally desmoplastic and pseudoglandular patterns and oncocytoid changes. Immunohistochemical studies showed that the tumor cells were uniformly positive only for S-100 protein and vimentin. Signet-ring cell melanoma is a rare histopathological variant of malignant melanoma with only a few described cases. To the best of our knowledge, this is the first case reporting a combination of the signet-ring cell melanoma with desmoplastic, pseudoglandular, and oncocytoid features.

Myoepitheliale Tumoren der Haut und des Weichgewebes

Myoepithelial neoplasms of skin and soft tissues comprise cutaneous mixed tumor (chondroid syringoma), mixed tumor of subcutaneous and deep soft tissues, myoepithelioma and rare malignant myoepithelioma (myoepithelial carcinoma). Myoepithelial tumors of skin and soft tissues are characterized by an extreme clinicopathological heterogeneity as in other anatomic locations. The neoplasms arise in childhood as well as in adults and are composed of epithelioid, histiocytoid, spindled, plasmocytoid and/or clear tumour cells in varying combinations, and are set in a myxoid or hyalinised intercellular matrix. Immunohistochemically, neoplastic cells stain positively for epithelial markers (pancytokeratin and/or epithelial membrane antigen), and often for S 100 protein. More rarely muscle actin, glial fibrillary acid protein, calponin, and p63 are expressed, whereas desmin is usually negative. The presence of at least moderate cytological atypia is associated with a significant risk for aggressive behavior and propensity for metastasis.

Basal cell carcinoma occurring in scar tissue following excision of a parotid gland pleomorphic adenoma

BACKGROUND

A 49-year-old patient presented with a basal cell carcinoma growing on scar tissue left following excision of a parotid gland pleomorphic adenoma.

OBJECTIVE

The objective was to determine whether the basal cell carcinoma had resulted from tumor spillage at the time of the pleomorphic adenoma excision.

METHODS

Substantial evidence is presented linking the two tumors.

RESULTS

The basal cell carcinoma most likely occurred as the result of tumor spillage at the time of the parotid gland pleomorphic adenoma excision.

CONCLUSIONS

Cutaneous connective tissue stroma plays a significant role in determining the differentiation of basal cell carcinomas.

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.