Primary myeloid sarcoma masquerading as an obstructing duodenal carcinoma

Abstract

Myeloid Sarcoma (MS), a rare extra hematopoietic carcinoma composed of blast cells, is located primarily in extramedullary sites such as skin, soft tissue, lymph nodes, and bone. MS usually presents in the setting of coexisting acute myeloid leukemia (AML) and myeloproliferative disorders. Gastrointestinal involvement (GI) is extremely rare from nonspecific abdominal symptoms to obstruction. Eight cases of myeloid sarcoma involving the duodenum including the current case have been reported, overall mean age being 40 years (range 17-71) and M : F ratio 7 : 1. The prognosis of patients with de novo MS cases has been reported to be better than those who have a coexisting leukemia. MS is a rare extramedullary tumor, which should be considered in the differential diagnosis of a soft tissue mass involving the duodenum, especially if there is a coexisting hematological disorder. De novo cases often progress to AML, and current therapy involves Daunorubicin- and Cytarabine-based chemotherapy. The wide cytogenetic and molecular heterogeneity of MS implies a potential role for more targeted MS therapies, which may offer a curative strategy.

Figure 1

Initial CT abdomen with contrast showing a diffuse 6.1 cm × 5.9 cm × 8 cm thickening of the wall of duodenum with adjacent encasement of the superior mesenteric artery.

Figure 2

Esophagogastroduodenoscopy image on the left shows edematous and eythematous mucosa of the 3rd portion of the duodenum. Image on the right shows an area of 5 mm of ulceration in the 4th portion of the duodenum.

Figure 3

(a) Duodenal biopsy showing infiltration of blastoid cells into the mucosa. (H&E original magnification, ×400). (b) Myeloperoxidase (MPO) staining reveals same population of cells staining positive for MPO (original magnification, ×400). (c) Tumor cells staining bright yellow (positive) for CD34 (original magnification, ×400). (Image courtesy of Dr Mu Su).

Figure 4

CT abdomen after 1 cycle of chemotherapy showing a decrease in size (2.9 cm × 3.5 cm × 4.4 cm tissue mass) in the distal duodenal mass.