Remission of metastatic primary mucinous carcinoma of the skin with anastrozole
Authors: Solomon Shockman, Lauren Krug, Nektarios Lountzis
Journal: Journal of the American Academy of Dermatology (2014)

To the Editor: An 80-year-old woman with a recurrent primary mucinous carcinoma of the scalp presented for Mohs surgery (Fig 1). After several stages of Mohs surgery, the tumor was deemed unresectable because of its depth and the extent of bone involvement. Clinical exam, computed tomography, positron emission tomography (PET) scan, and lymph node biopsy revealed mucinous carcinoma in the cervical, hilar, and mediastinal lymph nodes, as well as lung parenchymal involvement. The tumor cells were strongly positive for estrogen receptors (ERs), negative for progesterone receptors (PRs), GCDFP, and CK20. The patient underwent local radiation of the scalp and neck over 6 months. The patient was also started on anastrozole (Arimidex), an aromatase inhibitor, 1 mg daily due to the tumor cells' strong ER positivity. Follow-up PET scan showed no hypermetabolic focus on the scalp, neck, or chest. Five years after diagnosis, no signs of scalp recurrence or metastatic progression can be detected on physical exam or PET scan. Mammography and colonoscopy results continue to be negative. She continues to take and tolerate anastrozole therapy, which was complicated only by a slight decrease in bone density that was stabilized with weekly alendronate (Fosamax). Mucinous carcinoma of the skin can be locally invasive and approximately 30% recur after excision, but has low rate of regional metastasis through lymphatic spread (9.6%) and only 2% of cases are fatal.1Mendoza S. Helwig E.B. Mucinous (adenocystic) carcinoma of the skin.Arch Dermatol. 1971; 103: 68-78Crossref PubMed Scopus (170) Google Scholar It is recommended that patients undergo wide local excision, but recent data have shown Mohs micrographic surgery to be valuable in establishing clear margins and decreased recurrence.1Mendoza S. Helwig E.B. Mucinous (adenocystic) carcinoma of the skin.Arch Dermatol. 1971; 103: 68-78Crossref PubMed Scopus (170) Google Scholar, 2Halachmi S. Lapidoth M. Commentary: approach to the rare eccrine tumor.Dermatol Surg. 2011; 37: 1194-1195Crossref PubMed Scopus (4) Google Scholar Unfortunately, as in our case, the tumor is not completely resectable even using Mohs micrographic technique. Primary mucinous carcinoma of the skin (PMCS) can appear clinically and histologically identical to metastatic adenocarcinomas from other sites such as lung, breast, and colon.3Eckert F. Schmid U. Hardmeier T. Altmannsberger M. Cytokeratin expression in mucinous sweat gland carcinomas: an immunohistochemical analysis of four cases.Histopathology. 1992; 21: 161-165Crossref PubMed Scopus (42) Google Scholar It is important to distinguish between the 2 because of the differences in prognosis and treatment. Therefore, the use of imaging studies, immunohistochemical staining of biopsied specimens, and collaboration with oncology staff is often required. Unfortunately, PMCS and cutaneous metastases of mucinous breast adenocarcinoma can be immunohistochemically identical, making differentiation between the 2 impossible without clinical identification of a primary breast carcinoma. Similarities between ER-positive breast carcinomas and ER-positive PMCS, as in our case, suggest that aromatase inhibitors may be beneficial in PMCS. There are 2 major risk factors seen with aromatase inhibitors that should be carefully monitored: osteoporosis with fracture4Shapiro C.L. Aromatase inhibitors and bone loss: risks in perspective.J Clin Oncol. 2005; 23: 4847-4849Crossref PubMed Scopus (24) Google Scholar and cardiovascular events due to increased lipids.5Howell A. Cuzick J. Vascular effects of aromatase inhibitors: data from clinical trials.J Steroid Biochem Mol Biol. 2005; 95: 143-149Crossref PubMed Scopus (32) Google Scholar In order to prevent local invasion, recurrence, and the rare metastasis, the antiestrogenic medications may be beneficial in PMCS given its similarities to primary mammary mucinous carcinoma and the strong ER positivity found in these tumors.5Howell A. Cuzick J. Vascular effects of aromatase inhibitors: data from clinical trials.J Steroid Biochem Mol Biol. 2005; 95: 143-149Crossref PubMed Scopus (32) Google Scholar We suggest testing for ER/PR expression in PMCS and advocate for the potential use of aromatase inhibitor therapy in advanced disease.