Cutaneous Squamous Cell Carcinoma with Unicellular Mucoprotein Accumulation

Abstract

The difficulty of differentiating an epithelial skin tumour with partial adenoid histological features from a metastasis of an internal adenocarcinoma is exemplified by a case report of an 83-year-old woman. Histological, histochemical and ultrastructural results led us to suppose that two different carcinomas with metastases were present: an adenocarcinoma of the colon and a ‘unicellular muciparous squamous cell carcinoma of the skin’. The nosological proximity of the primary skin tumour to mucoepidermoid tumours and to sweat gland carcinoma of the ductular epithelium will be considered in more detail.

A Unique Case of Squamous Cell Carcinoma Showing Adenocarcinomatous Features with Focal Apocrine Differentiation

“…Squamous cell carcinomas with adenocarcinomatous differentiation have been less frequently seen. They include Bowen's disease with invasive carcinoma showing sweat gland differentiation (15,16), lymphoepitheliomalike carcinoma of the skin with adnexal differentiation (17,18), adenosquamous carcinoma (19)(20)(21), and carcinoma displaying both squamous and mucinous differentiation (22)(23)(24)(25). Among these neoplasms, adenosquamous carcinoma and squamous cell carcinoma with mucin-producing cells should be differentiated from our case.…”

“…Cutaneous squamous cell carcinomas occasionally show adnexal differentiation (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Many cases of squamous cell carcinoma with follicular differentiation have been reported and some were designated tricholemmal carcinoma (11)(12)(13)(14).…”

“…Microcystic adnexal carcinoma has characteristic histological appearances including both pilar and eccrine differentiation (8,9). Squamous cell carcinoma can contain specific structures suggesting pilosebaceous or glandular differentiation (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25).…”

Mucoepidermoid Carcinoma of the Skin: A Distinct Entity From Adenosquamous Carcinoma

“…One other case not included among these 7 cases from the literature may be an MEC of skin; this patient died of metastatic carcinoma, and the pattern of ''papillary adenocarcinoma'' was seen at autopsy. 26 All but 1 patient with cutaneous MEC was over the age of 50 years at diagnosis. 31 The head and neck region and the acral extremities were the sites of predilection.…”

“…10 Other examples of mucinous metaplasia of eccrine sweat ducts or within squamous cell carcinomas are documented in the literature. 11,20,26,27,33,44 Some years ago, it was pointed out that mucin-containing cells can be found in mixed tumors of the skin. 23 A final note concerns the classification of MEC of the skin.…”