Metastases to the breast from primary extramammary tumors – real diagnostic dilemma

Summary

Objective:
To address the difficulty and possible pitfalls in diagnostics of breast metastases from extramammary primaries - a pathobiological phenomenon that is not always thought of. To underline the open-minded differential diagnostic algorithm that is naturally weakened by dominant straightaway logistics in a routine contemplation. To emphasize the importance of complete and relevant clinical data including the anamnesis. To evaluate the effectiveness velocity and cheapness of immunohistochemistry at reaching the correct diagnosis.

Design:
Comprehensive study of the unusual pathogenetic setting based on personal experience with eight observations and literature review.

Setting:
Biopsy Lab s.r.o. and Šikl’s Department of Pathology, Charles University and Faculty Hospital, Pilsen.

Methods:
Detailed clinicopathologic characteristics and review of morphologic spectrum in nine cases of extramammary tumors metastatic to the breast (three melanomas, two small cell carcinomas, one carcinoma from salivary gland, ovary, kidney and prostate). Standard immunohistochemistry was used as a reliable tool for phenotypic evaluation.

Results:
In total nine cases, eight women and one man, were identified among 3238 of malignant breast tumors in the years 2005-2010. There were three melanomas, two small cell carcinomas and by one carcinoma from salivary gland, ovary, kidney and prostate. The age ranged from 43 to 81 years and maximum size of lesion spanned 7-31 millimeters. All specimens were core needle biopsy and only in one patient the past medical history concerning the nonbreast malignancy was known (ovarian serous carcinoma). Two neoplasms (one of the melanomas and small cell carcinomas) were the first sign of underlying malignant process ever; in this melanoma the clinical workout to disclose primary skin lesion failed. These two tumors were also the only ones, where the multiple or bilateral involvement of breast was clinically documented. There was evident other organs spread in three cases at the time of diagnosis (generalization in melanoma and prostate carcinoma; skin metastasis in salivary gland carcinoma) and axillary lymph nodes involvement in two melanomas. In five patients where follow-up was available, three died of tumor in interval from five to eighteen months (in turn melanoma, small cell and prostate carcinoma). Four original pathologic verdicts turned out to be wrong (two melanomas, salivary gland and prostate carcinoma); in three of them final correct diagnosis was established even after additional clinical information about morphologically verified malignancy in the past.

Key words:
breast, extramammary tumor, metastasis, melanoma, carcinoma, parotid gland, lung, kidney, ovary, prostate.