Myeloid sarcoma of the breast in an aleukemic patient:a rare entity in an uncommon location

Myeloid sarcoma (MS) is an extramedullary solid neoplasm of immature myeloid cells. These tumours usually develop in concurrence with or following acute leukemia. The breast is an uncommon site for presentation of this tumour, where it is often misdiagnosed as lymphoma or carcinoma.A 33- year-old female presented with a right breast lump in a private hospital, which was diagnosed as ductal carcinoma on lumpectomy. Subsequently she developed a lump in the left breast and a similar diagnosis of carcinoma was made on biopsy. A left mastectomy was performed. Histopathological examination revealed a tumour composed of mononuclear cells arranged in sheets and cords with round to oval vesicular nuclei and occasional prominent nucleoli. IHC for CK was very weak and focal. The tumour cells were immunonegative for ER, PR, Her2neu,epithelial membrane antigen, e-cadherin, CD3 and CD20. Diffuse immunopositivity for myeloperoxidase, CD34 and CD117 established a diagnosis of myeloid sarcoma. A histopathological review of the right breast lesion, with immunohistochemistry, also confirmed the diagnosis of myeloid sarcoma. Investigatory workup for acute myeloid leukemia, including bone marrow aspirate and biopsy and karyotypic studies, proved negative. The patient was treated with high dose cytarabine (HDAC) regimen and was disease free during the 12-month follow-up.Although extremely rare, awareness of such a presentation is crucial. This case also illustrates that careful histopathological review along with an expanded panel of immunohistochemistry is extremely important for recognizing such cases as a misdiagnosis can lead to unnecessary surgery and inappropriate therapy.

Spinal epidural granulocytic sarcoma preceding acute myelogenous leukemia

A rare case of spinal epidural granulocytic sarcoma (GS) preceding acute myelogenous leukemia is described. A 10-year-old boy presented with lower leg weakness. The initial diagnosis was a histiocytic lymphoma, and he was treated accordingly. No evidence of bone marrow involvement was found at that time. The correct diagnosis of epidural GS was made possible in retrospect by using immunoperoxidase staining for lysozyme fourteen months later when the patient showed the full-blown features of leukemia. This rare tumor should be considered in the differential diagnosis of an epidural mass with cord compression in patients with or even without acute leukemia, because early diagnosis followed by appropriate combined chemotherapy and radiation may obviate surgical intervention and eventually prevent leukemic transformation.