Microcystic adnexal carcinoma: Management options based on long‐term follow‐up

Abstract

Microcystic adnexal carcinoma (MAC), a recently described neoplasm that frequently affects the head and neck, presents a confusing problem for the clinician due to its unusual behavior. The individual cells have a bland microscopic appearance, and there is a predilection for neural invasion. Four cases of MAC are reported. All four cases demonstrate the difficulty with pathologic diagnosis. Follow-up of as long as 33 years begins to delineate the protracted nature of MAC. In addition, this paper includes the first report of a case of lymph node metastasis. Although resection may result in a significant defect, negative margins may not be achieved. Despite this, the defect can heal, as demonstrated by the cases described. In addition, MAC may recur many years later, irrespective of the status of the margins at the time of surgery. Given these unusual characteristics and the slowly progressive nature of MAC, strong consideration must be given to less radical surgical procedures, with close follow-up for grossly recurrent disease.

Treatment of nasal microcystic adnexal carcinoma with an expanded rotational forehead skin flap: A case report and review of the literature

“…Mitotic structures are rare in these tumor cells, and they lack significant atypia. MAC tumor cells invade the whole dermis, frequently invading the striated muscle, nerves, vascular adventitia, cartilage tissue and periosteum (1)(2)(3)13). Although MACs have the ability to locally invade tissues, very few cases have reported systemic metastasis and mortality.…”

“…However, further studies are required to identify a reliable immunohistochemical marker specific to MACs. Therapy for MACs remains a challenge, as the tumor-free margin is significantly more extensive than can be determined clinically and the tumors exhibit a marked tendency for perineural invasion (3)(4)(5). Numerous treatment modalities have been used to date, including standard excision (SE), MMS, irradiation and chemotherapy (6,16); however, a number of studies have found that MAC is not sensitive to radiotherapy and chemotherapy (5,17).…”

“…Microcystic adnexal carcinoma (MAC) is a rare, locally aggressive type of adenocarcinoma with low-grade malignancy and extremely low metastatic ability (1)(2)(3). Since the first report of a MAC in 1982 by Goldstein et al (1), only ~300 cases of MAC have been described to date.…”

“…MACs are most frequently located in the head and neck area (7); however, the occurrence of nasal MACs is extremely rare. MAC is usually diagnosed by detection of characteristic histological features (1)(2)(3). Histologically, MACs contain numerous keratin cysts, basaloid cells and squamous cell islands that form ductular and glandular structures, which often invade nerves (2,3).…”

“…These characteristics complicate the surgical treatment of MAC (8). There are several therapies to treat MAC, including standard excision (SE), Mohs micrographic surgery (MMS), irradiation and chemotherapy (3)(4)(5)(6); however, there is no consensus regarding the treatment of MAC due to its rarity. Furthermore, there is no reported incidence rate of MAC since it is so rare.…”