An unusual type of primary breast lymphoma ADRIAN DUMITRU1,2 MANUELA POPA1,2, MARIANA COSTACHE1,2, MARIA SAJIN¹˒² 1.Department of Pathology, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania 2.Department of Pathology, Emergency University Hospital, Bucharest, Romania Introduction 3 4 Primary breast lymphoma is a very rare entity accounting for 1.7-2.2% of extranodal lymphomas and approximately 0.5% of all breast malignancies. Breast involvement in Hodgkin’s lymphoma is extremely uncommon, with primary breast Hodgkin’s lymphoma even rarer. Diagnostic criteria for primary Hodgkin’s lymphoma of the breast are: the presence of sufficient tissue for diagnosis, close interaction between mammary tissue and lymphomatous infiltrate and no evidence or prior diagnosis of widespread lymphoma. Our case illustrates an unusual presentation of Hodgkin's lymphoma of the breast: clinically as inflammatory breast cancer and core biopsy as granulomatous mastitis, the final diagnosis requiring surgical biopsy. A 54-year-old woman, C.M, with two nodular, solid, painful left breast lesions, measuring 4x3 and 2x1 cm was referred to the Emergency University Hospital Bucharest in December 2014. Clinical examination of the lesions revealed inflammation and ulceration of the overlying skin, “peau d’orange” changes along with diffuse axillary erythema and enlarged axillary lymph nodes. The thoracic CT scan revealed that the skin lumps were part of a left 5x4 cm breast mass with adjacent left axillary lymphadenopathy. The core biopsy proved to be inconclusive. On cut section a heterogeneous, gray-white, unencapsulated mass, with hemorrhagic and necrotic areas and focal fibrous areas was discovered. The intraoperative aspect was suggestive for inflammatory breast cancer but the paraffin embedded tissue revealed a marked inflammatory granulomatous reaction with an atypical lymphomatous proliferation consistent with granulomatous mastitis, although it didn’t completely exclude a malignant origin. Microscopic examination also showed a nodular lymphoid malignant proliferation that infiltrates the adjacent mammary tissue. A proliferation of eosinophiles, plasma cells, giant pleomorphic lacunar Reed-Sternberg cells, Hodgkin cells and anaplastic multinucleated giant cells were observed to replace the normal architecture of the breast. Immunohistochemical investigations used to assess the phenotype and provide a definitive diagnosis were consistent with the nodular sclerosis variant of classic Hodgkin’s lymphoma. The postoperative recovery was uneventful and the patient was referred to a haematologist for further treatment. Figure1. Macroscopic aspect of the surgical specimen Figure2. Lacunar Reed-Sternberg cell with bilobed nucleus and prominent eosinophilic nucleoli (center) and numerous Hodgkin cells. (lower left) H.E. ob.20X 5 6 Case presentation Key words 7 8 Figure3. Broad bands of collagen in nodular sclerosing pattern of Hodgkin’s lymphoma. H.E.4X Figure4. Strong CD30 membrane positivity in Reed– Sternberg cells. Anti-CD30/ peroxidase conjugate and DAB chromogen, 20X. Figure5. Reed–Sternberg and Hodgkin cells selectively immunostained for CD15 marker. The staining is membranous and paranuclear (Golgi area). Anti-CD15/ peroxidase stain, 20X. Figure6. Positive nuclear PAX-5 immunoreactivity in Reed–Sternberg and Hodgkin cells. Anti-PAX5/ peroxidase stain, 20X. Figure7. Positive CD3 T-cell lymphocytes forming an abundant cellular infiltrate around Reed–Sternberg and Hodgkin cells. Anti-CD3/ peroxidase stain, 20X . Figure8. Scarce CD20 expression in B-cell lymphocytes around Reed–Sternberg and Hodgkin cells. Anti-CD20/ peroxidase stain, 20X. This case illustrates an unusual presentation of Hodgkin's lymphoma of the breast: clinically as inflammatory breast cancer and initial needle biopsy as granulomatous mastitis, the final diagnosis requiring surgical biopsy. Further immunohistochemistry guided the final diagnosis. Current information regarding this entity is limited, mainly build upon its rarity. In this paper we assess the clinical presentation, the step-by-step diagnosis and the importance of immunohistochemistry in this uncommon condition. ACKNOWLEDGEMENT This paper is partly supported by the Sectorial Operational Programme Human Resources Development (SOPHRD), financed by the European Social Fund and the Romanian Government under contract number POSDRU 141531 1 2 Conclusions