Microcystic adnexal carcinoma: Successful management of a large scalp lesion

Abstract

Microcystic adnexal carcinoma (MAC) is a rare, malignant cutaneous neoplasm. It is important for us to become more aware of it, as it is often misdiagnosed, either clinically or histopathologically. We report a case of an extensive scalp lesion that was successfully treated using a combination of resection and adjuvant radiotherapy.

An atypical presentation of extensive centrofacial microcystic adnexal carcinoma responding to radiation: A case report and review of the literature

“…It often presents as an indolent, non-ulcerated, smooth-surfaced, flesh-colored to yellowish asymptomatic nodule, papule, plaque, or cystic lesion with indistinct margins with a predilection for the head and neck, predominantly arising in the central face. 1,4,[11][12][13][14][15][16][17][18] It is paramount to include MAC as a differential diagnosis among the other head and neck lesions to enable early diagnosis and treatment to reduce morbidity and mortality. Deep incisional or excisional biopsy for histopathology is the gold standard for initial diagnosis.…”

“…Deep incisional or excisional biopsy for histopathology is the gold standard for initial diagnosis. 16,17 Mohs is considered the gold standard of treatment for MAC. To date, there is insufficient evidence whether radiation is an effective monotherapy in patients with MAC due to rarity of the disease and the limited use as a management option.…”

“… 1 – 26 It is characterized as a malignant, aggressive, and locally invasive tumor with a high recurrence rate. 2 – 4 , 8 , 9 , 11 – 17 , 19 MAC typically does not metastasize; however, there are reports of local and distant progression of the disease. 1 , 13 , 15 Although recognized as a distinct clinicopathologic entity, 3 MAC has proven to be diagnostically challenging as it can mimic other similar neoplasms.…”

“… 1 , 13 , 15 Although recognized as a distinct clinicopathologic entity, 3 MAC has proven to be diagnostically challenging as it can mimic other similar neoplasms. 3 , 6 , 16 , 17 Consequently, in addition to its rarity, there is often inadequate initial treatment. Clinically, MAC typically manifests as an indurated, growing flesh-colored plaque although variations of clinical morphology have been reported.…”

“…Clinically, MAC typically manifests as an indurated, growing flesh-colored plaque although variations of clinical morphology have been reported. 1 , 4 , 11 – 18 Microscopically, the tumor often extends beyond clinical margins, spreading locally into the dermal, subcutaneous, and occasionally perineural tissues. 4 Histological features of MAC include infiltrated well-differentiated nests and cords of keratinocytes displaying follicular and ductal differentiation in a sclerotic stroma.…”