Basal cell carcinoma of the skin with areas of squamous cell carcinoma: Basosquamous cell carcinoma?

Abstract

The diagnosis of basosquamous cell carcinoma is controversial. A review of cases of basal cell carcinoma showed 23 cases that had conspicuous areas of squamous cell carcinoma. This was distinguished from squamous differentiation and keratotic basal cell carcinoma by a comparative study of 40 cases of compact lobular and 40 cases of keratotic basal cell carcinoma. Areas of intermediate tumour differentiation between basal cell and squamous cell carcinoma were found. Basal cell carcinomas with areas of squamous cell carcinoma may be called basosquamous carcinoma. Basal cell carcinomas have been described with nuclear atypia,' multinucleate tumour giant cells,' 2 and other unusual or aggressive features.3 Only one case of basal cell carcinoma with areas of squamous cell carcinoma has been reported, and this was termed basosquamous cell carcinoma.4 This controversial diagnosis is accepted by some authors-8 and rejected by others.9-'2 This paper reports a histopathological study of 23 cases of basal cell carcinoma of skin in which there were conspicuous areas of squamous cell carcinoma.

Basal cell carcinoma: biology, morphology and clinical implications

“…The metatypical BCC (equated by some authors with 'basosquamous carcinoma' 39 ) is, in our view, a form of aggressive growth BCC with infiltrating jagged tongues of tumor cells, some of which manifest an abortive peripheral palisade and clearcut basaloid morphology, admixed with other areas that show intercellular bridge formation and/or cytoplasmic keratinization ( Figure 11). Clinching the diagnosis is the presence of a coexistent classic nodular or superficial component.…”

“…We distinguish these neoplasms from keratotic BCC, which is most often a nodular BCC with central squamous differentiation, and from the mixed basal cell-squamous cell carcinomas that represent a collision between two clonally distinctive and geographically separate neoplasms in the same biopsy or excision specimen. Metatypical BCC is the subtype of BCC that can be confused with squamous cell carcinoma and which promotes controversy considering its precise histomorphologic classification, 39,40 as it shows both basal cell and squamous cell carcinoma differentiation in a continuous fashion. 15,41 One must recognize that use of the terms 'metatypical BCC' and Infiltrative growth BCC: histomorphology.…”

“…These include, but are not restricted, to keratotic BCC, 39 infundibulocystic BCC (Figure 12), 42,43 follicular BCC, [44][45][46][47] which shows collision features with pilomatricoma, pleomorphic BCC ( Figure 13), 48,49 BCC with eccrine differentiation, [50][51][52] BCC with sebaceous differentiation, the fibroepithelioma of Pinkus (Figure 14), 53 and the BCC with myoepithelial differentiation. 54 Keratotic BCC Also known as pilar BCC as it appears to differentiate along pilosebaceous lines, the keratotic BCC manifests large basaloid tumor nests that are rounded and show central keratinization and degeneration.…”

“…As with other nodular BCCs, the stroma is neither proplastic nor highly collagenized, and mitotic activity is minimal as is the presence of individual cell necrosis. 39 True hair production is absent.…”

Pulmonary Metastasectomy in Cutaneous Basosquamous Cell Carcinoma: Case Report

“…Tanısı tartışmalı olsa da, skuamöz hücreli kanser alanları içeren BHK olgularının BSHK olarak tanımlanabi-leceği ileri sürülmüştür. 23 olguluk seride BHK zemininde dikkat çekici derecede skuamöz hücre adacıkları görülmüş olması bu savı desteklemektedir [3]. Hastamızda da BSHK tanısı bu tanım çerçevesinde konmuştur.…”