How to differentiate mucinous eccrine carcinoma from cutaneous metastasis of breast carcinoma?

Abstract

IntroductionApproximately 25% of the patients with breast cancer develop cutaneous metastases. The major differential diagnosis of cutaneous metastatic breast cancer is represented by sweat gland carcinoma which accounts for about 0,05% of all cutaneous neoplasms [1,2]. Treatment and prognoses of these two entities differ radically making accurate histologic diagnosis mandatory. Indeed, the presentation of these two entities is often distinct. Cutaneous metastasis of breast carcinoma presents as multiple lesions in patients with a previous diagnosis of primary breast carcinoma, whereas, sweat gland carcinoma presents as a single cutaneous lesion in patients with unknown history of breast cancer. However, cutaneous metastases of breast carcinoma can be difficult to distinguish from sweat gland carcinoma when the diagnosis is based mainly on histologic features and the clinical circumstances are unknown by the pathologist. We describe a new case of sweat gland carcinoma which presented a real diagnostic dilemma. Case ReportA 60-year-old woman presented with a frontal scalp mass which appeared 6 months ago. The patient was asymptomatic and had no history of trauma. Physical examination revealed a painless mass measuring 0.5 cm. Incision biopsy was performed and microscopic findings consisted in a dermal malignant tumor proliferation arranged in clumps and lobules surrounded by an abundant mucoid stroma and separated by thin fibrous septa. Tumor cells were monomorphic, rounded with cytoplasmic vacuoles of mucus secretion and atypical nucleolated nuclei (Fig. 1a, 1b). Immunohistochemical findings showed a nuclear expression of estrogenic and progesteronic antigens (Fig. 1c). Tumor cells didn't express HER2-Neu antigen (Fig. 1d). These microscopic findings were suggestive of a cutaneous metastasis of an eventual mucinous breast carcinoma. A mammography and a chest MRI were performed targeting the primary breast lesion and showed no breast lesion. Facing these radiologic findings, we concluded to a cutaneous mucinous eccrine carcinoma. So that, the lesion was totally resected and the patient presented no complications after one year of follow up.Case Reports DOI: 10.7241/ourd.20124.77 Our Dermatol Online. 2012; 3(4): 346-348Date of submission: 09.07.2012 / acceptance: 09.08.2012 AbstractEccrine skin tumors are rare and represent only 0,05% of all cutaneaous neoplasms. They represent a pitfall especially with cutaneous metastases of carcinoma which are more frequent. We report the case of a 60-year-old woman presented with a frontal scalp mass whose histologic and immunohistochemical features concluded initially to a cutaneous metastasis of breast carcinoma. The diagnosis was reviewed because of the absence of a breast lesion. The final diagnosis was primary sweet gland carcinoma. Histologic distinction between cutaneous metastatic breast carcinoma and primary cutaneous adnexal neoplasms can be very challenging or even impossible. This case illustrates this difficulty and puts emphasis on the necessity of keeping in ...