Medusa head‐like granules in squamous cell carcinoma with differentiation toward a hair follicle structure

Abstract

A case of squamous cell carcinoma (SCC) with regional lymph node metastasis in a 69-year-old Japanese man is reported. The tumor was characterized by the proliferation of peripheral basaloid, inner squamoid, and glycogen-rich cells, the presence of trichilemmal keratinization, and the presence of ladder-like, membrane-coating granules. These findings suggested that this tumor differentiates toward a hair-follicle structure. The most interesting feature of this tumor was the presence of medusa head-like granules in the cytoplasm of the clear squamoid cells adjacent to the keratinized cells. We have been unable to find any other studies of these granules in squamous cell carcinoma.

Cutaneous squamous cell carcinoma: a comprehensive clinicopathologic classification. Part One

“…[182][183][184] Follicular squamous cell carcinoma Although most SCCs arise in the epidermis, occasional cases of SCC arising in hair follicles have been reported. [186][187][188] It has long been known that SCC can arise from follicular epithelium, and the cases have shown both squamous as well as follicular and sebaceous differentiation. 7,186 Diaz-Cascajo et al 187 recently reported 16 cases of SCC developing in hair follicles, most arising in sun-damaged skin, typically on the face of elderly persons.…”

“…A broadspectrum anti-HPV antibody was also negative in all cases. 187 Yamamoto et al 188 reported a case of SCC with differentiation toward follicular epithelium, demonstrating both squamoid and glycogen-rich cells, with tricholemmal keratinization and so-called 'medusa head' granules. The later was a unique finding, suggesting differentiation toward the innermost cells of the outer root sheath.…”

Proliferating trichilemmal tumour: p53 immunoreactivity in association with p27Kip1 over‐expression indicates a low‐grade carcinoma profile

“…This has prompted some dermatopathologists to advance the opinion that PTT is a low‐grade adnexal carcinoma 6 or merely a variant of squamous cell carcinoma 7 . Indeed, squamous cell carcinoma has been always considered to be the main differential diagnosis of PTT, 4 and in small samples the distinction can be almost impossible, moreover taking into account that some squamous cell carcinomas can display features of hair follicle differentiation 8 …”

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

“…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).…”