This is an interesting review of a rare group of tumours which together comprise the adnexal sweat gland carcinomas. Although there are only 22 patients, this is the largest cohort ever published. The authors summarise the clinical presentation, stage, management and outcomes. Age ranged from 48 to 83 years and 59% were female. The vast majority of tumours were slow growing, being present for months to years before presentation. The various carcinoma subtypes were seven mucinous, four microcystic adnexal, four endocrine mucin producing, two eccrine, two apocrine, two poorly differentiated adnexal and one hydroadenocarcinoma. Five showed perineural invasion, three of which were recurrent tumours and two of which were microcystic adnexal carcinomas. Two of the five with perineural invasion had residual disease after completion of local surgical treatment. One had lymph node involvement after a fourth local recurrence, and the other died with cavernous sinus involvement. Two patients had orbital invasion, but none developed distant metastases. Perineural involvement, microcystic adnexal carcinoma histological subtype and a stage greater than T2b were associated with a higher risk of recurrence.
The authors suggest adjuvant radiotherapy may be indicated for these tumours or after any recurrent disease. They found no difference in recurrence between those resected by Mohs micrographic surgery and those removed by wide excision with histological margin control.