LAUSR

Dear Editor, A 53-year-old woman is presented with dysmenorrhea and vomiting, lasting for few months and recently worsening. Blood tests highlighted slight leukopenia (3.460 cell/mmc), anemia (10.1 g/dL), and mild lactate dehydrogenase (LDH) increase (509 IU/L; range 0–248). No history of hematological malignancies was reported. Magnetic resonance imaging (MRI) of the abdomen revealed marked thickening of the uterus wall, multiple retroperitoneal lymphadenopathy, and right hydroureteronephrosis. On the clinical suspect of uterine tumor, the total hysterectomy was performed. Grossly, the uterus appeared increased in size (105 × 85 × 80 mm), with a diffuse thickening of the myometrium; the endometrium was unremarkable (Fig. 1a). Histologically, the uterus was diffusely infiltrated by middle-sized cells, with round nucleus, prominent nucleolus, and scarce cytoplasm (Fig. 1b, H&E stain, 400×). CD45, CD34 (Fig. 1c, 400×), myeloperoxidase, CD56, and S100 protein (Fig. 1d, 200×) were strongly expressed. The diagnosis ofmyeloid sarcoma (MS)wasmade. Bone marrow (BM) biopsy did not show any evidence of leukemic infiltration or other myeloid neoplasms. Computed tomography-positron emission tomography (CT-PET) scan revealed a diffuse extramedullary disease, involving the mediastinum and abdomen. BM reassessment at progression, after the first cycle of treatment, confirmed the absence of BM involvement. Despi te induct ion chemotherapy (Cytarabine/ Daunorubicin based scheme, "7+3"), the patient died of progressive disease after two courses of treatment. MS is commonly diagnosed simultaneously or prior to acute myeloid leukemia (AML); it may constitute the evolution of previous myeloid neoplasms or precede AML relapse after treatment. Isolated MS is commonly reported as AML relapse after allogeneic BM transplant, perhaps due to BM microenvironment changes after the procedure [1, 2]. MS involving the gynecological tract is uncommon, with fewer than 100 cases reported in the literature [3]. It becomes even more rare as isolated form, being potentially misdiagnosed as solid neoplasm or aggressive lymphoma. Gynecological MS preferentially affects the uterus and the ovary [3], but cases of MS involving the vulva, vagina [4], and even placenta [5] have been reported. In the present report, the MS diagnosed in the uterus was associated to a widespread disease, which was however completely extramedullary. The expression of CD56 (neural cell adhesion molecule, NCAM), observed in our case, has been linked to neoplastic homing patterns in specific AML categories [6, 7] and has been observed in other cases of gynecological MS [3, 8]. S100 protein expression is rarely described in MS and, to the best of our knowledge, never reported before in gynecological MS, making the diagnosis even more complex. The accurate morphological and immunohistochemical evaluation is essential to render the correct diagnosis. Fluorescence in situ hybridization (FISH) analysis of formalin-fixed paraffin-embedded (FFPE) samples, not performed in our case, may help in stratifying risk categories for these patients. * Giovanni Martino [email protected]