A Pediatric Primary Anaplastic Large Cell Lymphoma of the Breast: Unusual Presentation in an Unexpected Clinical Setting

Abstract Objectives Anaplastic large cell lymphoma (ALCL) constitutes approximately 15% of childhood lymphoma cases, showing male predominance. We report a rare case of ALCL presenting as a breast mass in a pediatric patient. Methods The patient is a 14-year-old female who consulted for a lump in the left breast of 2 months’ duration that later progressed to an ulcerative lesion with axillary lymphadenopathy. The lesion was being treated as an abscess for 5 months but was unresponsive to antimicrobial treatment. Excisional biopsy showed breast tissue with overlying ulcerated skin and abscess with sinus formation. Histologically, it showed a mixture of inflammatory cells, including lymphocytes, neutrophils, plasma cells, and scattered large cells, which had abundant gray cytoplasm, large irregular nuclei, and prominent nucleoli. Numerous abnormal mitoses were seen. Results Immunohistochemical stains were done to delineate the phenotype of large cells. The anaplastic cells were positive for CD30 and MUM1 and negative for CD20, CD79a, CD3, ALK, CD68, S-100, EMA, CK7, mammaglobin, CK5/6, GCDFP, CD15, CD68, CD138, CAM5.2, AE1/AE3, and EBER (EBV in situ hybridization). They had a high proliferation index, 50%, by Ki-67 and expressed a null phenotype (CD4–, CD8–). Clonal rearrangement involving the TCR gamma gene was present. CT scan demonstrated lytic rib and vertebral lesions that were PET positive. Conclusion Presence of sheets of large anaplastic cells that are CD30+ and ALK– is consistent with the diagnosis of ALCL. Diagnosis of primary breast lymphoma necessitates exclusion of primary cutaneous lymphoma and systemic lymphoma with secondary breast and cutaneous involvement. This is an unusual case of ALCL arising in a young female as a breast mass masquerading as an abscess.