Are You Confident of the Diagnosis?
Mucinous carcinoma is most frequently seen in the periobital area. It is a rare, slow growing, malignant tumor that arises from the deepest portion of the eccrine sweat duct. Lesions most commonly are slow growing, solitary, and asymptomatic.
Characteristic findings on physical examination
The color of the lesions varies from yellow- tan to red, grey and even blue. The overlying skin sometimes appears translucent due to distention. Lesions are generally exophytic nodules but reports have also described variations such as pedunculated, crusted and fungating. The most frequent sites of primary cutaneous mucinous carcinoma are: eyelid 38%, other facial locations 20.3%, scalp 16%, axilla 10%.
Expected results of diagnostic studies
A biopsy of a suspected lesion will have the following characteristics. Mucinous carcinomas are wider in the deep dermis than on the epidermal surface and can extend into the subcutis. The tumor islands appear suspended in a sea of pale-staining mucin. The clustered epithelial cells are small with uniform, somewhat hyperchromatic, cuboidal nuclei. Mitotic figures are rare. The islands of are typically in clusters and form tubules, but cribriform areas may also be noted (Figure 1, Figure 2, Figure 3, Figure 4, Figure 5).
Staining characteristics of mucinous eccrine carcinoma are listed below.
PAS+, diastase resistant, alcian blue positive at pH 2.5, consistent with sialomucin
colloidal iron +
low molecular weight cytokeratin +
S100 variably +
Estrogen receptor (ER) and Progesterone receptor (PR) + has been reported
a lactalbumin variably +
Gross cystic disease fluid protein (GCDFP)-15 variably positive
monoclonal antibodies to high molecular weight cytokeratin – typically non-reactive.
The differential diagnosis for mucinous carcinoma clinically would also include other benign and malignant eccrine tumors, basal cell carcinoma, epidermoid cyst, pyogenic granuloma, hemangioma and Kaposi’s sarcoma. Clinically and histopathologically, the differentiation between primary cutaneous mucinous carcinoma, malignant eccrine tumors and metastatic adenocarcinoma lesions ( breast, colon, prostate, lung, salivary glands, ovaries, pancreas and kidney) can be most difficult, necessitating a careful history, physical examination, and appropriate imaging studies.
With respect to differentiating between primary cutaneous mucinous carcinoma and other sweat gland carcinomas, in most other tumors, mucin is present within the epithelial islands. In mucinous carcinoma, the islands float in a sea of sialomucin, a nonsulfated mucoprotein with acid and neutral moieties. This sialomucin is sialidase labile.
The distinction between primary cutaneous mucinous carcinoma and adenocarcinoma is difficult to make on biopsy. Although there are some subtle differences, such as CDX2 or CK20 staining in metastatic gut carcinoma, clinical correlation and testing for possible primary tumors should be considered in every patient.
Who is at Risk for Developing this Disease?
There has not been a risk factor identified for primary cutaneous mucinous carcinoma other than reports of preceding trauma in a few case reports. The median age of onset is 63 years and there is a male predominance of 2:1. Ethnic distribution is 62% white, 32% African-American and 4% Asian.
What is the Cause of the Disease?
Primary cutaneous mucinous carcinoma is a rare malignancy of the eccrine sweat duct. Specific carcinogenic factors for the malignant transformation have not been identified nor does there seem to be a familial component for this rare tumor.
Systemic Implications and Complications
Due to the rarity of primary cutaneous mucinous carcinoma (less than 130 cases have been reported to date) and potential misdiagnosis of metastatic adenocarcinoma, all patients should undergo a work-up to rule out the possibility of a primary adenocarcinoma at a separate location that became metastatic (breast, colon, prostate, lung, salivary glands, ovaries, pancreas, and kidney). Since the periorbital, face and scalp are the most typical locations of primary mucinous eccrine carcinoma, if lesions are elsewhere this would increase the index of suspicion for a possible metastatic etiology.
A complete skin examination should be done including a lymph node exam to rule out metastatic lesions from the initial site of primary cutaneous mucinous carcinoma, as well as lymph node metastasis.
Rates of local recurrence after conventional excisions vary are reported from 13% on the axilla to as high as 34% in the eye and foot area. Regional metastais rates are reported to be 11% overall (all sites included) but can be as high as 36% on the scalp. The rate of widespread distant metastases has been reported as 3%. The rate of regional lymph node metastasis has been reported between 5% and 15%.
The only treatment effective for primary mucinous eccrine carcinoma is surgical removal. This can be done with standard excision using a margin of 1 cm if possible; alternatively, Mohs micrographic surgery has been used to treat this malignancy. Immunoperoxidase-guided Mohs micrographic surgery, with the additional use of the immunoperoxidase stain low-molecular-weight cytokeratin , has been reported. This could enhance the sensitivity for detection of mucinous carcinoma, and may help contribute to complete tumor removal. Radiation and chemotherapy have not been effective in the treatment of mucinous eccrine carcinoma.
Optimal Therapeutic Approach for this Disease
Complete removal of the lesion with a clear margin is the only recommended treatment for primary mucinous eccrine carcinoma.
Primary mucinous eccrine carcinoma has a local recurrence rate greater than 36% after surgical excision. Patients should be seen for skin examination at least twice a year and educated in self-skin examination to look for local recurrence and possible regional lymphadenopathy.
Unusual Clinical Scenarios to Consider in Patient Management
Due to the rarity of primary cutaneous mucinous carcinoma (less than 130 cases have been reported to date) and potential misdiagnosis of metastatic adenocarcinoma, all patients should undergo a work-up to rule out the possiblity of a primary adenocarcinoma at a separate location that became metastatic (breast, colon, prostate, lung, salivary glands, ovaries, pancreas, and kidney). Since the periorbital region, face, and scalp are the most typical locations of primary mucinous eccrine carcinoma, if lesions are observed elsewhere, the index of suspicion for possible metastatic etiology should be increased.
What is the Evidence?
Ajithkumar, TV, Nileena, N, Abraham, EK, James, FV, Nair, K. “Bone marrow relapse in primary mucinous carcinoma of skin”. Am J Clin Oncol. vol. 22. 1999. pp. 303-4. (Case report of a 70-year-old male with primary mucinous carcinoma in whom a metastatic relapse developed nearly 2 years later. The metastatic focus was found in his bone marrow.)
Bellezza, G, A. Sidoni, A, Bucciarelli, E. “Primary mucinous carcinoma of the skin”. Am J Dermatopathol. vol. 22. 2000. pp. 166-70. (Excellent overall review of mucinous carcinoma from a clincal and histological perspective.)
Bertagnoli, RD, Cook, L, Goldman, GD. “Bilateral primary mucinous carcinoma of the eyelid treated with Mohs surgery”. Dermatol Surg. vol. 25. 1999. pp. 566-8. (Mucinous carcinoma treated with Mohs surgery. Discusses advantages of using mohs surgery for removal of mucinous eccrine carcinoma on the eyelid.)
Breiting, L, Christensen, L, Dahlstrøm, K, Breiting, V, Winther, JF. “Primary mucinous carcinoma of the skin: A population-based study”. Int J Dermatol. vol. 47. 2008. pp. 242-5. (Study that attempts to determine the incidence of this rare tumor.)
Breiting, L, Dahlstrøm, K, Christensen, L, Winther, JF, Breiting, V. “Primary mucinous carcinoma of the skin”. Am J Dermatol. vol. 29. 2007. pp. 595-6. (Excellent overall review of mucinous carcinoma from a clinical and histological perspective.)
Cabell, CE, Helm, KF, Sakol, PJ, Billingsley, EM. “Primary mucinous carcinoma in a 54-year-old man”. J Am Acad Dermatol. vol. 49. 2003. pp. 941-3. (Case report with a review of the literature and concise review.)
Friednash, M, Golitz, L, Bohlmeyer, T. “Periorbital solitary nodule and multiple small papules in a 63-year-old women. primary mucinous carcinoma (nodule) and syringom (papules)”. Arch Dermatol. vol. 133. 1997. pp. 1161(Report of a case of mucinous carcinoma. The patient also had multiple syringomas.)
Jih, MH, Friedman, PM, Kimyai-Asadi, A, Goldberg, LH. “A rare case of fatal primary cutaneous mucinous carcinoma of the scalp with multiple in-transit and pulmonary metastases”. J Am Acad Dermatol. vol. 52. 2005. pp. S76-80. (Case report of metastatic mucinous carcinoma and discusses the fatal outcome.)
Karimipour, DJ, Johnson, TM, Kang, S, Wang, TS, Lowe, L. “Mucinous carcinoma of the skin”. J Am Acad Dermatol. vol. 36. 1997. pp. 323-6. (Excellent review of mucionous carcinoma. Discusses diagnosis, and therapy.)
Warycha, M, Kamino, H, Mobini, N, Hale, EK. “Primary mucinous carcinoma with direct histopathologic evidence of lymphatic invasion”. J Drugs Dermatol. vol. 5. 2006. pp. 655-8. (Report of lymphatic invasion by a primary cutaneous mucimous carcinoma.)
Snow. “Mucinous eccrine carcinoma of the eyelid”. Cancer. vol. 70. 1992. pp. 2099-2014.
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