Mammary Infection by Tropheryma Whipplei: A Novel Case Report of Whipple Disease

Infection by the actinobacterium Tropheryma whipplei was originally described as a malabsorptive enteropathy known as classic Whipple disease (WD). Extraintestinal manifestations were subsequently documented, with isolated or predominant involvement of organs such as brain, heart and lung, even in the absence of digestive symptoms. Diagnosis at novel sites is based on microscopic identification of foamy macrophages with PAS-positive, Gram-positive and acid-fast bacilli–negative histochemical staining, and may be complemented by molecular testing. Infection of breast tissue by T. whipplei has never been described, and documenting such a case is the purpose of this report. We report the case of a 31-year-old Venezuelan woman, previously healthy, with progressive enlargement of breast masses over two years, without associated symptoms. Five years earlier, she had undergone liposuction with autologous fat grafting to the breasts. On physical examination, three firm, mobile nodules not adherent to deep planes were identified: one 7 cm retroareolar nodule in the right breast and two periareolar nodules in the left breast measuring 3 and 5 cm. Mammography classified the lesions as suspicious but with low likelihood of malignancy (BI-RADS 4A). Core needle biopsies revealed a granulomatous process with foamy macrophages containing PAS-positive and Gram-positive intracytoplasmic granules, negative for acid-fast bacilli, compatible with T. whipplei infection. Molecular testing was not performed, and upper endoscopy was normal. Standard therapy for WD with ceftriaxone followed by sulfamethoxazole-trimethoprim was initiated, resulting in complete regression of the nodules and a definitive diagnosis of mammary Whipple disease. This is the first documented case of WD in breast tissue, expanding the spectrum of extraintestinal manifestations of this infection. Isolated presentation in breast tissue without classic systemic involvement raises questions about the immunopathogenesis of T. whipplei infection, including possible local changes associated with prior autologous fat grafting. The characteristic histopathological findings remained the cornerstone of diagnosis, reinforcing that microscopy is essential to identify tissue tropism of this actinobacterium in previously undescribed locations. Finally, the excellent response to standard antimicrobial therapy confirms its effectiveness even in anatomical sites not previously reported.