• Microcystic adnexal carcinoma is a low grade sweat gland carcinoma.
• Other names for this entity include malignant syringoma, and sclerosing sweat gland carcinoma.
• This tumor develops on the central face, including the eyelids.
• Eccrine carcinomas, including microcystic adnexal carcinoma, express follicular stem-cell markers, suggesting origin from the folliculosebaceous apocrine unit (Mahalingam, Am J Dermatopathol 2010).
• Sweat gland carcinomas include eccrine carcinoma, apocrine carcinoma, mucinous carcinoma, and microcystic adnexal carcinoma.

Microcystic adnexal carcinoma has been reported to arise in the context of immunosuppression and prior radiotherapy.

• Basal cell carcinoma
• Squamous cell carcinoma
• Syringoma
• Desmoplastic trichoepithelioma

Natural history

• Microcystic adnexal carcinoma typically is deeply invasive locally because it eludes clinical recognition for a long time, often years.
• In the study by Baker et al. (OPRS 2017), microcystic adenexal carcinoma was found to be a particularly aggressive subclass of sweat gland carcinomas, with 2 of the 4 patients showing perineural invasion, local recurrence, and extension into the cavernous sinus and maxillary sinus.  This study of sweat gland carcinomas had no patients with evidence of distant metastasis. 

Medical therapy

• There are no reported medical treatments for microcystic adnexal carcinoma.

Radiation

• When the diagnosis is delayed and recurrence occurs, especially with evidence of perineural spread it is reasonable to treat with adjuvant radiotherapy (Clement, OPRS 2005).
• Baker et al. recommended adjuvant radiation for lesions with evidence of perineural invasion on pathology. (OPRS 2017)
• Radiation therapy for facial microcystic adnexal carcinoma has been described as primary and treatment (Pugh, Head Neck 2012).
• Some have questioned the adequacy of radiotherapy as primary treatment although it has the advantage of avoiding disfiguring surgery (Baxi, J Med Imaging Rad Oncol 2010).
• Ocular morbidity with radiotherapy can be significant and the usual total dose is 50-60 Gray, delivered in standard fractionation.

Surgery

• Wide local excision is the preferred treatment.
• Mohs surgery is an option for MAC (Leibovitch, Ophthalmologica 2006)
• Deep and wide surgical margins are needed (Diamantis, Dermatol Clin 2011).

Other management considerations

• None.
• Close follow up is recommended for surveillance of recurrence

Common treatment responses, follow-up strategies

• Local recurrence is common with microcystic adnexal tumor, due to the deep invasive nature of the tumor.
• With adequate tumor excision the recurrence rate is low after surgical excision, without adjuvant radiotherapy (Leibovitch, Ophthalmologica 2006).

Morbidity for these tumors is related to the extent of tumor involvement, the need for surgical excision and effects of radiotherapy when used.

In the SEER database analysis described above for MAC the overall 10 year survival was 86%.

• However, there is only a single case in the literature of tumor related death due to microcystic adnexal carcinoma (Ohta, Dermatol Surg 2004).
• There are rare cases of systemic metastases; the survival outcome for some is not known (Eisen, Dermatol Surg 2005).

Microcystic adnexal carcinoma was first described by Goldstein in 1982 (Goldstein, Cancer 1982).

1. Baxi S et al. Microcystic adnexal carcinoma of the skin: the role of adjuvant radiotherapy. J Med Imaging Rad Oncol 2010; 54:477-82.
2. Baker MS, Yin VT, Ivan D, et al.  Epidemiology and prognosis of primary periocular sweat gland carcinomas.  Ophthal Plast Reconstr Surg 2017;33:101-105.
3. Clement CI, Genge J, O’Donnell BA, Lochhead AG: Orbital and periorbital microcystic adnexal carcinoma. Ophthal Plast Reconstr Surg 2005; 21:97.
4. Diamantis SA, Marks VJ. Mohs micrographic surgery in the treatment of microcystic adnexal carcinoma. Dermatol Clin 2011; 20:185-90.
5. Eisen DB, Zloty D. Microcystic adnexal carcinoma involving a large portion of the face: when is surgery not reasonable? Dermatol Surg 2005;31:1472-7.
6. Fu T et al. Congenital microcystic adnexal carcinoma. Arch Dermatol 2011; 147:256-7.
7. Goldstein DJ, Barr RJ, Santa Cruz DJ. Microcystic adnexal carcinoma: a distinct clinicopathologic entity. Cancer 1982; 50:566.
8. Hoppenreijs VP, Reuser TT, Mooy CM, de Keizer RJ, Mourits MP. Syringomatous carcinoma of the eyelid and orbit: a clinical and histopathological challenge. Br J Ophthalmol 1997;81:668.
9. Liyanage SE et al. Delayed diagnosis of microcystic adnexal carcinoma in progressive eyelid distortion. Arch Ophthalmol 2010;128:132-5.
10. Leibovitch I, Hulligol SC, Richards S, et al: Periocular microcystic adnexal carcinoma: management and outcome with Mohs’ micrographic surgery. Ophthalmologica 2006; 220:109.
11. Mahalingam M et al. Expression of stem-cell markers (cytokeratin 15 and nestin) in primary adnexal neoplasms-clues to etiopathogenesis. Am J Dermatopathol 2010; 32:774-9.
12. Marshall J, Mortimore R, Sullivan T. Sclerosing sweat duct carcinoma of the orbit. Orbit. 2003; 22:165.
13. Ohta M et al. Metastatic microcystic adnexal carcinoma: an autopsy case. Dermatol Surg 2005;30:957-60.
14. Ong T et al. Microcystic adnexal carcinoma of the eyebrow. OPRS 2004;20:122-5.
15. Peterson CM, Ratz JL, Sangueza OP: Microcystic adnexal carcinoma: First reported case in an African American man. J Am Acad Dermatol 2001; 45:283.
16. Pugh TJ, Lee NY, Pacheco T, Raben D: Microcystic adnexal carcinoma of the face treated with radiation therapy: a case report and review of the literature. Head Neck 2012; 34;1045.
17. Seltheyer K, Nelson P, Kutzner H, Patel RM: The immunohistochemical differential diagnosis of microcystic adnexal carcinoma, desmoplastic trichoepithelioma and morpheaform basal cell carcinoma using BerEP4 and stem cell markers. J Cut Pathol 2013; 40:363.
18. Smart DR et al. Microcystic adnexal carcinoma: the first reported congenital case. Pediatr Dermatol 2011;28:35-8.
19. Wu-Chen, WY et al. Unusual presentation of primary orbital microcystic adnexal carcinoma. J Neuroophthalmol 2011;31:147-50.
20. Yugueros P, Kane WJ, Goellner JR: Sweat gland carcinoma: a clinicopathologic analysis of an expanded series in a single institution. Plast Reconstr Surg 1998;102:705.
21. Yu JB et al. Surveillance, Epidemiology, and End Results (SEER) database analysis of microcystic adnexal carcinoma (sclerosing sweat duct carcinoma) of the skin. Am J Clin Oncol 2010;33:125-7.