Neuroendocrine differentiation in basal cell carcinoma

Abstract

Basal cell carcinoma (BCC) is the prototypical basaloid tumor of the skin. It may show various patterns simulating other cutaneous tumors due to its pleomorphism. It may have an unusal pattern of differentiation such as squamous, sebaceous, apocrine, eccrine, pilar, and endocrine differentiation. In order to establish the relative frequency of neuroendocrine differentiation in BCC, we performed a retrospective study of 33 consecutive BCCs using conventional immunohistochemistry with two neuroendocrine antibodies: Chromogranine A and synaptophysine. The age of the patients ranged from 17-83 years with mean of 65 years. The male to female ratio was 16:17. In immunohistochimestry, Chromogranine A was seen in 72.2% (24/33) while Synaptophysine was positive in 9.09% (3/33). Their expression was cytoplasmic and membranous and was seen in the periphery of these tumors in the overlying cells. Positive staining of chromogranine A was high (75-100% of tumors cells) in 9%, intermediate (25-75% of tumors cells) in 33% of cases and relatively low (<25%) in 30.3% of cases.

Under‐recognized immunoexpression of “neuroendocrine markers” and “myoepithelial markers” in basal cell carcinomas: Does it indicate true neuroendocrine and myoepithelial differentiation?

“…Immunoexpression of synaptophysin was negative (0%, 0/10; clone 27G12, prediluted; Nichirei) in my BCC panel and infrequent (9%, 3/33) in a previous study. 3 Synaptophysin was immunoexpressed in BCCs at a relatively high rate (18%, 12/66) in another study 2 ; however, this result should be interpreted with caution because the figures showed synaptophysin immunostaining in stromal cells, as well as weak synaptophysin staining in tumor cells.…”

“…I observed chromogranin A immunostaining (polyclonal, dilution: 1:4; Nichirei) in 7 (70%) of the 10 BCCs noted above, and reported rates are 27% (18/66) 2 and 72.2% (24/33). 3 In general, neither marker was expressed in all tumor cells; instead, expression was usually patchy Unlike CD56 and chromogranin A, synaptophysin, a third "neuroendocrine marker," is rarely expressed in BCCs. Immunoexpression of synaptophysin was negative (0%, 0/10; clone 27G12, prediluted; Nichirei) in my BCC panel and infrequent (9%, 3/33) in a previous study.…”

Neurofilament is superior to cytokeratin 20 in supporting cutaneous origin for neuroendocrine carcinoma

“…Neurofilament (Cell Marque, Rocklin, CA, USA; mouse monoclonal clone 2F11, prediluted) and CK20 (Cell Marque; Confirm TM rabbit monoclonal antibody, 1:200 dilution) immunohistochemistry was performed using the Ventana automated immunostainer (Ventana, Tucson, AZ, USA). [5][6][7] Neurofilament staining was performed on all tumours. CK20 staining was performed on all extracutaneous SmCC, all CK20-negative MCC and a subset of CK20-positive MCC.…”

“…Standard diagnostic immunohistochemistry for MCC includes cytokeratin 20 (CK20), neuroendocrine markers and often thyroid transcription factor 1 (TTF‐1). Neuroendocrine markers (including chromogranin A, synaptophysin and/or CD56) are expressed in MCC, but may also be expressed in other cutaneous carcinomas such as basal cell carcinoma, and do not exclude extracutaneous SmCC or other poorly differentiated metastases. TTF‐1 expression is relatively specific for SCLC in comparison to MCC, but is not expressed in approximately 15% of SCLC, and may be expressed in unusual cases of MCC .…”

Cutaneous basal cell carcinoma mimicking small cell carcinoma

“…Architectural and immunohistochemical features of small cell carcinomas universally reveal neuroendocrine differentiation, and this molecular trait has been theorized to underlie the platinum‐sensitive nature of the disease . Neuroendocrine differentiation of solid tumors is not unique to small cell carcinomas and historic as well as contemporary series have documented this feature in cutaneous basal cell carcinomas. Given the different management of small cell carcinoma and basal cell carcinoma, accurate diagnostics remain critical to ensure optimal tumor control while limiting treatment toxicities.…”