A Rare Case of Extramedullary Relapse of Multiple Myeloma Causing Bowel Obstruction

Abstract

Extramedullary myeloma, defined by presence of plasma cells outside the bone marrow, is a rare entity accounting for about 3-9% of all cases. It usually is aggressive with a median survival of <6 months. It is also associated with adverse prognostic factors including 17p deletions and high-risk gene profiles. While common extramedullary sites include bones, there have been several case reports of hematogenous extramedullary myeloma to the liver, lungs, pancreas, breast, skin, and soft tissues. Extramedullary myeloma to the mesentery is a rare entity with only a handful of cases reported. We present a case of 69-year-old man presenting with relapse of multiple myeloma to the mesentery, resulting in bowel obstruction to highlight the various presentations of myeloma.

Figure 1

CT scan of the abdomen without contrast revealing mesenteric thickening with edema.

Figure 2

(a) Bone marrow infiltrated by plasma cells. (b) Bone marrow immunohistochemistry revealing CD138 positive cells. (c) Bone marrow immunohistochemistry positive for kappa light chains. (d) Bone marrow immunohistochemistry negative for lambda light chains. Mesenteric invasion (e) by myeloma cells (10x) and (f) by plasma cells (40x).

Figure 3

Lytic lesions on the skull.

Figure 4

Lytic lesions on the L femur.