Thymoma with Concomitant Pure Red Cell Aplasia, Good's Syndrome and Myasthenia Gravis Responding to Rituximab

Abstract

Thymomas are often associated with a variety of autoimmune diseases, mostly myasthenia gravis. The association of thymomas with both pure red cell aplasia (PRCA) and Good's syndrome is exceedingly rare. To the best of our knowledge, the combination of a thymoma with manifestations of myasthenia gravis, PRCA, and Good's syndrome, as in our case herein, has not been described before in the medical literature. We present a 90-year-old man initially diagnosed with an asymptomatic thymoma. Later, he developed generalized muscle weakness and was found to have severe anemia. He was diagnosed with PRCA, myasthenia gravis and Good's syndrome. He responded to rituximab with restoration of bone marrow erythroid maturation and stabilization of red blood cell counts.

Keywords: Good’s syndrome; Myasthenia gravis; Pure red cell aplasia; Response; Rituximab; Thymoma.

Fig. 1

Lymphocyte-rich thymoma type B1, H&E needle-core biopsy (mag. 100x & 200x) with scattered inconspicuous epithelial cells immunostaining with CK AE1/AE3 (c) (mag. 400x) (a, b)

Fig. 2

A schematic representing the change of hemoglobin with time during the course of treatment. The black arrows represent the timing of rituximab dosing

Fig. 3

Bone marrow aspirate following rituximab treatment revealing increased precursor erythroblasts (arrow) and polychromatic normoblasts (arrowhead) (mag. 1000x) (a). Separate areas with precursor erythroblasts (arrow) and orthochromatic normoblasts (arrowhead) (mag. 1000x), a finding consistent with recovery of the erythroid lineage (b)