CASE SUMMARY

A 56-year-old man presented to the GI clinic with abdominal pain and swelling due to malignant intra-abdominal ascites and lymphadenopathy. On physical examination, a 2-cm painless, firm palpable right outer-quadrant breast mass was detected. The breast mass had developed spontaneously several weeks prior to examination. The patient denied any prior history of trauma to the breast. The patient was adopted, and thus was unsure of any family history of breast cancer. The patient's medical history was significant for a recent liver transplant 3 months earlier due to liver failure from cirrhosis related to hepatitis C and alcohol. He was currently taking immunosuppressive medications (neoral cyclosporine, mycophenolate mofetil, and prednisone) to prevent rejection.

DIAGNOSIS

High-grade B-cell lymphoma with extensive necrosis

IMAGING FINDINGS

Craniocaudal and mediolateral oblique mammograms (figure 1) and sonogram (figure 2) were performed. The mammograms demonstrate a 1.2 ¥ 1.8 cm microlobulated high intensity mass in the mid-outer breast. There are no associated microcalcifications or evidence of skin thickening or retraction. The marker corresponds to the palpable lesion. Incidental note is make of moderate gynecomastia. The sonogram shows a solid mass with microlobulations and contains slightly irregular margins. There is mild posterior acoustic enhancement. Following the breast imaging studies, the patient underwent a biopsy of the breast lesion.

DISCUSSION

Posttransplant lymphoproliferative disorders (PTLD) are an unfortunate complication of immunosuppression following organ trans-plantation. It is estimated that 1% to 4.6% of patients undergoing organ transplantation will develop PTLD, with the highest incidence occurring in heart- and lung-transplanted patients.1 The temporal incidence of PTLD ranges from 1 to 211 months, with the mean incidence reported to occur as early as 4 months.1 There appears to be a relationship with the type and dosage of immunosuppression medication required to prevent rejection and PTLD.2 Compared with the general population, transplant patients tend to have more aggressive lymphomas, with a higher proportion of non-Hodgkin lymphoma (NHL) versus Hodgkin lymphoma (93% versus 65%).1 It is important to emphasize that PTLD more commonly involves the extra-nodal sites as compared with the non-PTLD population. The most common sites of PTLD are the gastrointestinal tract, the transplanted organ, and the central nervous system.3 On pathologic examination, the PTLD specimens tend to have a more polymorphous appearance than the "classical" non-Hodgkin's lymphomas in the nontransplanted population.3 The majority of these tumors arise from B-lymphocytes with <15% arising from T-lymphocytes. There is evidence that Epstein-Barr virus (EBV) is a significant contributor to the pathogenesis of posttransplant lymphoproliferative disorders. This is felt to occur because of the immunosuppressive drugs given to prevent organ rejection. These medications primarily suppress T-cell lymphocyte function, thus selectively allowing the uncontrolled proliferation of B-cells when infected with EBV.

The treatment of PTLD involves an aggressive approach. Immunosuppressive medications are frequently reduced or changed in an attempt to reduce the T-cell deficiency.2 This must be carefully monitored, however, as there is a fine line between immunosuppression and organ rejection. Local therapy, including surgical resection and/or radiation, is frequently attempted to gain local control. Occasionally, systemic chemotherapy is provided for those patients refractory to the reduction in immunosuppression.2 Sepsis and other complications of immunosuppression are a significant cause of mortality. A mortality rate of 70% has been reported for patients presenting with PTLD more than 1 year after transplantation. In those patients who have responded to the reduction in immunosuppression, however, there has been a more favorable outcome.2