p63 and smooth muscle actin expression in low-grade spiradenocarcinomas in a case of CYLD cutaneous syndrome.

Low-grade spiradenocarcinoma is a rare skin tumor, with fewer than six reported cases, arising in the context of CYLD cutaneous syndrome (CCS; syn: Brooke-Spiegler syndrome [BSS]). We report two independent cases of spiradenocarcinoma arising in a 50-year-old man with CCS. The tumors grew rapidly, prompting clinical excision. The histologic features in our cases corresponded to the salivary gland type basal cell adenocarcinoma-like pattern, low grade (BCAC-LG), that has been previously recognized as a recurrent finding in CCS. We performed genetic testing of the patient and found a novel mutation in CYLD. Recognition of low-grade spiradenocarcinoma can be difficult for the pathologist as the features can be subtle, especially in those cases where the transition from benign to malignant tumor is gradual. We examined p63 and smooth muscle actin (SMA) expression patterns in BCAC-LG and compared it with the expression pattern in the precursor spiradenoma. Our report provides information on two rare tumors in the context of CCS and suggests that the pattern of p63 and SMA staining may aid pathological detection of the BCAC-LG subtype of spiradenocarcinoma.

Squamous cell and adnexal carcinomas of the skin.

The diagnosis and treatment of adnexal cancers continues to pose a challenge to a wide range of clinicians. The diseases are a diverse lot, owing to the wide range of skin structures and large surface area. Early recognition and treatment are key to improved outcomes. Education of the patients as to their role in their care, especially early detection, is also of crucial importance. Further study may yield information to improve diagnosis and treatment.

Nonmelanoma skin cancer.

Nonmelanoma skin cancer (NMSC) is the most common form of malignancy in humans. The incidence of NMSC continues to increase despite increased awareness and sun-protective measures. If neglected or mismanaged, NMSC can cause significant morbidity and even death. The most common forms of NMSC on the head and neck include basal cell carcinoma, squamous cell carcinoma, sebaceous carcinoma, eccrine porocarcinoma, Merkel cell carcinoma, atypical fibroxanthoma, and microcystic adnexal carcinoma. Surgery is the mainstay of treatment (standard excision, Mohs micrographic surgery, curettage); however, other modalities exist, including radiation, topical immunomodulators, photodynamic therapy, and new systemic medications.

Uncommon cutaneous neoplasms of the head and neck.

This article concentrates on the less-common cutaneous malignancies such as merkel cell, atypical fibroxanthoma, malignant fibrous histiocytoma, dermatofibrosarcoma protuberans, microcystic adnexal carcinoma, and sebaceous carcinoma. The clinical and histopathologic descriptions of each, most current and emerging etiologies, diagnosis, staging, treatment, and prognosis are discussed.

Microcystic adnexal carcinoma: an uncommon tumor with debatable origin.

BACKGROUND: Microcystic adnexal carcinoma is an uncommon skin appendage neoplasm exhibiting both pilar and sweat duct differentiation. This tumor remains a subject of controversy as to its differentiation profile, histogenesis, and classification which is reflected in the nomenclature used to designate the neoplasm in question. Beyond this controversy the tumor remains a diagnostic challenge because of its rarity, the histologic mimicry it may display, and its banal cytologic appearance; it also poses a therapeutic challenge, as it is characterized by slow but aggressive and destructive local growth extending beyond clinical margins together with a high tendency for perineural invasion and recurrence. OBJECTIVE: We report two cases of this unusual tumor illustrating some of its characteristics. Our review emphasizes the divergent opinions concerning its differentiation profile and its origin. An organoid nevus as the origin of microcystic adnexal carcinoma in one of our patients is discussed in this context.

Microcystic adnexal carcinoma arising in the setting of previous radiation therapy.

While there are several reports of microcystic adnexal carcinoma developing in patients within sites of previous therapeutic irradiation, this relationship is not well described in the dermatologic literature. We report a case of a 42-year-old man with a remote history of therapeutic irradiation following surgical resection of periorbital rhabdomyosarcoma. Subsequently, he developed multiple basal cell carcinomas and a microcystic adnexal carcinoma within the field of irradiation. The histologic features were those of a classic microcystic adnexal carcinoma, with well differentiated nests and cords of keratinocytes displaying follicular and ductular differentiation infiltrating diffusely into the reticular dermis. Dense fibrosis was present surrounding the neoplastic keratinocytes. Nuclear atypia and mitotic figures were not identified. A carcinoembryonic antigen (CEA) stain demonstrated glandular differentiation. It is important for dermatologists to be aware of the apparent relationship between the rare microcystic adnexal carcinoma with its innocuous scar-like clinical appearance and prior local radiation therapy.