TCL-525 Salivary Myeloid Sarcoma: A Challenging Diagnosis.

Abstract

A female in her late 30s from North Africa with no past medical history presented with four months of an expanding left face and neck mass that led to facial disfigurement (Viral screen HIV, HCV & HBV negative, EBV unknown). Ultrasound of the neck showed an enlarged left submandibular salivary gland with increased echogenicity with a surrounding inflammatory process and reactive lymphadenopathy, and no visible stone. Magnetic resonance imaging (MRI) of the neck revealed an infiltrating soft tissue enhancing mass surrounding the left side mandibular body, and it was locally infiltrating the left side submandibular, sublingual salivary gland left parotid, left side masseter muscle, myeloid muscle, and left side medial pterygoid muscle, and prominent bilateral cervical lymphadenopathy. Contrast tomography (CT) of the neck, chest, abdomen, and pelvis was unremarkable apart from cervical lymphadenopathy. Biopsy of the submandibular gland immunohistochemistry (LCA, BCL2, CD7 +VE, & focally for CD3 & CD5, while they are negative for PanCK. CD20, PAX5, CD79a, MUM1.BCL6.CD30, CD2, CD56, & TdT, Ki67 40%) suggested the diagnosis of high-grade T-cell lymphoma. Bone marrow biopsy was normal. The patient received five cycles of cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisone (CHOEP). A follow-up CT scan and positron emission tomography (PET) scan showed stable disease size and hypermetabolism. Revision of immunohistochemistry was strongly positive for CD45, CD33, CD34, CD43 and CD107, and negative for CD3, CD4, CD8, CD30, CD68, CD11c, CD20, CD79a and MPO. The diagnosis was updated to myeloid sarcoma (granulocytic sarcoma). The patient received 7+3 doxorubicin and cytarabine with impressive results clinically, followed by 3 high-dose cytarabine consolidation. Three months following completion of treatment, facial swelling recurred, and a PET scan showed hypermetabolic activity consistent with recurrence. The patient is undergoing salvage therapy (cytosar & etoposide) in preparation for a bone marrow transplant. We present a challenging case of salivary gland myeloid sarcoma that was initially misdiagnosed as T-cell lymphoma; interestingly, her bone marrow was not involved at the time of diagnosis. A high index of suspicion is warranted in CD3 negative and CD20 negative lymphoma, and expanded immunohistochemistry earlier may improve diagnosis.