A Brownish-grey Plaque with Ulceration on the Nasolabial Area: A Quiz

Yuichi Yoshida1, Tatsushi Shiomi1,2, Masahisa Shindo1, Yoshiko Suyama3, Bin Nakayama3 and Osamu Yamamoto1

1Division of Dermatology, Department of Medicine of Sensory and Motor Organs, 2Department of Organ Pathology, and 3Divison of Plastic Surgery, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago-shi, Tottori 683-8503, Japan. E-mail: yxy@grape.med.tottori-u.ac.jp

A 57-year-old Japanese man presented with a 10-year history of a plaque on his face. The lesion had gradually increased in volume. Physical examination revealed a brownish-grey plaque, approximately 5 × 5 cm in size, with ulceration on the right nasolabial area (Fig. 1a). Dermoscopy showed a milky-red area with some milia-like cysts and dilated vessels on the surface (not shown). Histopathological examination revealed a poorly circumscribed tumour invading deeply into the dermis and subcutis. Tumour nests composed of atypical basaloid cells were embedded in a desmoplastic stroma. Some keratinous cysts and cystic glands were seen in the mid-dermis. Small ductal or glandular structures were also seen in the deep dermis (Fig. 1 b, c). Immunohistochemically, most of tumour cells were positive for carcinoembryonic antigen (CEA).

Fig. 1. (a) A brownish-grey plaque with ulceration located on the right upper cutaneous lip/cheek junction. (b) Tumour nests of atypical basaloid cells were embedded in a desmoplastic stroma. Some keratinous cysts and cystic glands were seen in the mid-dermis. (c) Small ductal or glandular structures were seen in the deep dermis.

doi: 10.2340/00015555-1172

What is your diagnosis? See next page for answer.

A Brownish-grey Plaque with Ulceration on the Nasolabial Area: Comment

Acta Derm Venereol 2011; 91: XX–XX (contd).

Diagnosis: Microcystic adnexal carcinoma

Microcystic adnexal carcinoma (MAC) is a rare cutaneous neoplasm, first described by Goldstein et al. in 1982 (1). Clinically, the tumour presents as a flesh-coloured indurated nodule or plaque that is most commonly seen on the skin around the lip (2). Although metastasis is extremely rare, the local recurrence rate is relatively high (3). Therefore, a long-term careful follow-up is necessary after excision. It has been reported that Mohs micrographic surgery is useful for treatment (4). Histopathologically, MAC is characterized by a superficial component of keratinous cysts as well as by a component of small strands of cells in the deep dermis within a hyalinized stroma.

Differential diagnosis mainly includes sclerosing/infiltrative basal cell carcinoma and desmoplastic trichoepithelioma. However, it is sometimes difficult to make a correct diagnosis (4). Although there is no specific tumour marker for MAC, a combination of immunohistochemical stains, such as CEA, epithelial membrane antigen, some cytokeratins and Ki-67, may be helpful for diagnosis (5). In most cases of MAC, tumour cells with ductal structures are positive for CEA and the level of Ki-67 expression is usually low. In the present case, many tumour cells were positive for CEA and some tumour cells were positive for epithelial membrane antigen. In addition, less than 5% of the tumour cells were Ki-67-positive.

It is important for dermatologists to include MAC in the differential diagnosis of skin tumours on the face.

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