CLINICAL HISTORY:

Signs and symptoms:  None other than that is visually noticeable.

Previous Treatment:  The family reports that there was a previous shave biopsy by a dermatologist but the pathology was not known or available. Also, the family self-treated the area at home through the use of freezing products.

Other information:  At approximately 2 years of age the patient fell at home, hitting and lacerating her chin and lip on a metal sliding door track.

PHYSICAL EXAM:

Firm, 0.8cm x 0.5cm, flesh-colored nodule on the left, lower, lateral cutaneous lip. Otherwise, the physical exam was normal.

LABORATORY TESTS:

None

DERMATOHISTOPATHOLOGY:

Biopsy - Desmoplastic follicular neoplasm extending to margins and base. Recommend reexcision for clear margins.

Pathologist consultation during MOHS - Follicular neoplasm with nests of uniform cells with central keratinous microcysts. In one section the cysts were broad, but in subsequent sections interconnected smaller nests were seen. Trichoepithelioma was considered but final diagnosis was deferred to dermatopathologist consultation.

Dermatopathologist - Microcystic adnexal carcinoma was favored as a primary biopsy diagnosis after review. The MOHS specimen was described as tissue with horizontally oriented dermal fibrosis associated with increased capillaries and sparse inflammatory infiltrate. The final diagnosis was scar with retained suture and margins free of pathology with no residual microcystic adnexal carcinoma identified.

Secondary Pathologist - Residual microcystic adnexal carcinoma and changes consistent with previous surgical intervention that were both completely excised.

DIFFERENTIAL DIAGNOSIS:

1.   Calcified Pilomatrixoma
2.   Macrocystic Adnexal Carcinoma
3.   Syringoma
4.   Trichoepithelioma
5.  

SCROLL DOWN FOR ANSWER AND DISCUSSION.

CORRECT DIAGNOSIS:

DISCUSSION:

MAC Discussion

Microcystic adnexal carcinoma (MAC) is a rare, malignant tumor. There are approximately 300 reported cases. It is commonly classified as a low-grade sweat gland carcinoma. The tumor is most commonly found in the head and neck region (85%), with a predilection for the nasolabial area (especially the upper lip) and the periorbital skin. It shows aggressive local invasion but has little metastatic potential (8 reported cases). Most cases of MAC occur in whites, with 5 cases reported in African Americans and 1 case in a Japanese woman. There is a slight female predominance; however, there is no significant sexual predilection. Most cases reported have been from 11 to 90 years old, with it most commonly occurring in the second to the eighth decade of life, peaking around 40-60 years of age. Radiation (both UV and Therapeutic) has been thought to play a role in the cause of microcystic adnexal carcinoma.
A deep incisional or excisional biopsy is required. Superficial biopsies lead to misdiagnosis because deep extension and perineural invasion are key features of the tumor. The important differentials histologically are syringoma, desmoplastic trichoepithelioma and morpheaform basal cell carcinoma. Duct formation, if present, would favor MAC over desmoplastic trichoepithelioma. Further, keratocysts with mild atypia and little mitosis would favor MAC over syringoma. Distinction from a morpheaform basal cell carcinoma can be made by the demonstration of duct, intracytoplasmic lumen formation and zonation of the tumor from the epidermis, which is typically seen with MAC. Ductal formation is rare in basal cell carcinoma. If seen, it is usually in nodular subtypes.

Full Case Discussion

Pt is a 7yo female presenting to clinic with complaint of a “bump on the skin” on her left lower lip for possibly 2 to 4 years. She denies any complaints associated with the lesion. Her immunizations have all been received and are current. She has no medical or surgical history. Her maternal grandmother had non-melanoma skin cancer. The only medication taken is a multivitamin and she has no know allergies to medication.
On examination there is a firm, 0.8cm x 0.5cm nodule on the left, lower, lateral cutaneous lip. Excisional biopsy was done to rule out pilomatrixoma.

Biopsy was returned as a desmoplastic follicular neoplasm that extended to the margins and the base. Recommendation was made for reexcision for clear margins and MOHS surgery was decided to be the most appropriate management. The family agreed and the patient was scheduled for surgery.

The dermatologist took a first stage and based on the microscopic findings, a pathology consultation was requested. Evaluation noted a follicular neoplasm with nests of uniform cells with central keratinous microcysts. In one section the cysts were broad, but in subsequent sections interconnected smaller nests were seen. Trichoepithelioma was considered but final diagnosis was deferred to dermatopathologist consultation. This was discussed with the family and it was noted that the margins appeared to be free of tumor. It was decided to defer further intervention until conclusive diagnosis was obtained.

The defect site was primarily closed and the patient instructed to return to the clinic in a few days for the final diagnostic report. Upon return, diagnosis was still in question so it was discussed that further surgical evaluation by a facial plastic surgeon may be most appropriate since excision had already reached the lip musculature and final pathology diagnosis could indicate that more extensive surgical intervention may be necessary. The family agreed to pursue this recommendation.

The specimen had been resent to the original reporting dermatopathologists for further evaluation. After comparison with the original slides, microcystic adnexal carcinoma was favored as a primary biopsy diagnosis. The MOHS specimen was described as tissue with horizontally oriented dermal fibrosis associated with increased capillaries and sparse inflammatory infiltrate. The final diagnosis was scar with retained suture and margins free of pathology with no residual microcystic adnexal carcinoma identified. This diagnosis was sent to the facial plastic surgeon that was to see the patient and he requested another pathology evaluation locally. That pathologist reported the specimen to be residual microcystic adnexal carcinoma and changes consistent with previous surgical intervention that were both completely excised. The included comment was that MAC is locally aggressive and typically occurs in individuals slightly older than our patient. No further management was undertaken by the facial plastic surgeon.

The patient returned to the dermatology clinic within a week of the defect primary closure for suture removal. The site was well-approximated and healing appropriately without complication. Followup in one month was recommended for reevaluation of surgical site.

TREATMENT:

Treatment for MAC can be difficult, with local reoccurrence possible without proper margin control. Mohs micrographic surgery is the current treatment of choice. Clinical margins are difficult to define, and MMS offers an excellent way of following the infiltrating nature of the tumor and tracing perineural involvement.











After biopsy, MOHS surgery and microscopic evaluations, the lesion was found to be Microcystic Adnexal Carcinoma. The lesion was completely excised and the defect closed primarily.

REFERENCES:

Goldstein DJ, Barr RJ, Santa Cruz DJ. Microcystic adnexal carcinoma: a distinct clinicopathologic entity. Cancer. Aug 1 1982;50(3):566-72.

Cooper PH, Mills SE. Microcystic adnexal carcinoma. J Am Acad Dermatol. May 1984;10(5 Pt 2):908-14.

Abbate M, Zeitouni NC, Seyler M, Hicks W, Loree T, Cheney RT. Clinical course, risk factors, and treatment of microcystic adnexal carcinoma: a short series report. Dermatol Surg. Oct 2003;29(10):1035-8.

Thomas CJ, Wood GC, Marks VJ. Mohs micrographic surgery in the treatment of rare aggressive cutaneous tumors: the Geisinger experience. Dermatol Surg. Mar 2007;33(3):333-9.

Fernandez-Figueras MT, Montero MA, Admella J, de la Torre N, Quer A, Ariza A. High (nuclear) grade adnexal carcinoma with microcystic adnexal carcinoma-like structural features. Am J Dermatopathol. Aug 2006;28(4):346-51.

Friedman PM, Friedman RH, Jiang SB, Nouri K, Amonette R, Robins P. Microcystic adnexal carcinoma: collaborative series review and update. J Am Acad Dermatol. Aug 1999;41(2 Pt 1):225-31.

Chiller K, Passaro D, Scheuller M, Singer M, McCalmont T, Grekin RC. Microcystic adnexal carcinoma: forty-eight cases, their treatment, and their outcome. Arch Dermatol. Nov 2000;136(11):1355-9.

Cooper PH. Carcinomas of sweat glands. Pathol Annu. 1987;22 Pt 1:83-124.

McAlvany JP, Stonecipher MR, Leshin B, Prichard E, White W. Sclerosing sweat duct carcinoma in an 11-year-old boy. J Dermatol Surg Oncol. Nov 1994;20(11):767-8.

Additional Comment:

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