Pigmented papillary carcinoma of male nipple mimicking melanoma

Abstract

Background and objective: Primary melanomas of breast and carcinomas with pigment rich melanocytes are well known entities. Melanoma in nipple-areola complex is extremely rare and in differential diagnosis must be distinguished between Paget disease, melanoma from extramammary sites and other invasive carcinomas. We present a case of invasive papillary carcinoma of male nipple with melanin laden tumor cells. Methods: A 71-year old male patient presents with lobulated grayish tumor of the right nipple measuring 2x1, 3 cm elevated above the skin surface 1cm. The lesion was surgically removed with skin excision 0,7x 0,5x 0,5cm. The specimen was formalin-fixed and paraffin-embedded, routinely stained with HE. Additional immunohistochemical analysis was performed with CK7, ER, SMA, S-100, and Melan A. Results: The gross specimen on cut sections revealed solid white to brown tumor, well demarcated at the base and ulceration of overlying epidermis. Histomorphology of the sections showed papillary structures with tall columnar cells overlying fibrovascular cores, as well as micropapillary formations. There were areas of solid and cribriform growth pattern. Microcalcifications were diffusely present. There were accumulated melanophages in subepithelial tissue and melanin granules were also found in tumor cells. Immunohistochemical analysis showed that tumor cells were positive for CK7, with strong and diffuse nuclear stain for ER, with complete absence of myoepithelial cell on SMA stain. Melan A and S-100 were negative. Although rare, a diagnosis of pigmented papillary carcinoma was made. Conclusion: Pigmented carcinomas of breast are rare. When they are localized in areolar region the diagnosis should be carefully made to exclude lesions with melanocytic differentiation. The pigmentation should be considered also as a result by proximity to epidermis. The distinction between benign and malignant papillary lesions is quite difficult in most cases. The prognosis of patients with papillary carcinoma is relatively favorable.