[Metaplastic carcinoma of the breast as a second neoplasm. Report of a case].

A patient with a metaplastic breast carcinoma as a second primary carcinoma after a renal pelvis neoplasm, an association not described before, is reported. Her first admission in October 1983 was due to a silent hematuria secondary to a mass in the right kidney. The histopathologic diagnosis was a grade II transitional cell carcinoma of the renal pelvis without distant or regional lymph nodes metastasis. Four years later, a right upper and outer quadrant breast mass was detected. Malignant disease was diagnosed by needle biopsy, and a simple mastectomy (Madden type) was performed. The histologic evaluation showed a metaplastic carcinoma with a pseudosarcomatous appearance: fifteen axillary lymph nodes showed only lymphoreticular hyperplasia. After surgery, the patient received locoregional radiotherapy. At present, eight years and five months after the first malignant neoplasia and four years and four months after the second malignancy, the patient is asymptomatic and free of disease. We comment the prevalence of multiple primary malignant neoplasms, the risk of developing a second tumor after a renal pelvis carcinoma, and the histologic findings and prognostic factors in metaplastic breast carcinoma.