Secondary ALK-Positive Anaplastic Large Cell Lymphoma Masquerading as Inflammatory Breast Cancer

Background: Secondary breast lymphoma accounts for 0.12% of breast malignancies. Anaplastic large cell lymphoma (ALCL) metastases to the breast are rare considering lymphoid tissue is a minor component of the breast. We describe a case of secondary ALK-positive ALCL identified during workup of inflammatory breast cancer in the setting of diffuse erythema, induration, and pitting lymphedema of the right breast with weeping serous fluid in a septic patient. Case Presentation: A 28-year-old female presented with septic shock and two weeks of right breast pain, erythema, swelling, and fever. Imaging demonstrated a mass in the right axillary/sub-pectoral region and bilateral axillary, mediastinal, supraclavicular, and retroperitoneal lymphadenopathy. Physical exam demonstrated tenderness, diffuse erythema, induration, pitting lymphedema of the right breast with palpable lymphadenopathy concerning for inflammatory breast cancer. Punch biopsy was performed. Immunohistochemical analysis revealed CD30 and CD45 positivity. Fluorescent in-situ hybridization (FISH) reflex revealed ALK (2p23). Subsequent nodal biopsies revealed hallmark cells. The cumulative findings were indicative of ALK-positive ALCL. Conclusion: This presentation underscores the importance of including lymphoma within the differential during workup of suspected inflammatory breast cancer.