Case of the Month: Dermatopathology

History

A 74-year-old man; status: post-orthotopic heart transplant. In 1999, secondary to ischemic cardiomyopathy and subsequent renal transplant; in 2009, secondary to calcineurin nephrotoxicity; now presents with a firm, asymptomatic cutaneous nodule on the leg.

Case Study

Pathologic Features

The biopsy specimen consists of a dense dermal infiltrate of CD138 positive atypical plasma cells with prominent nucleoli and binucleate forms. Kappa and lambda in-situ hybridization demonstrates distinct lambda restriction. Epstein Barr Virus in-situ hybridization shows diffuse positivity within the atypical plasma cell population. Ki-67 labeling index is approximately 40%.

Differential Diagnosis

Primary cutaneous plasmacytoma and secondary cutaneous plasmacytoma — These would also show a diffuse infiltrate of plasma cells; however, the plasma cells would not label with Epstein-Barr virus in-situ hybridization.



DIAGNOSIS

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Discussion

PTLD is a process characterized by a lymphoid proliferation in the clinical setting of transplantation.

  1. It typically presents in the lymph nodes, GI tract, liver or lung but very rarely presents in the skin. PTLD is separated into four categories by the WHO: early lesions, polymorphic, monomorphic and classical Hodgkin-lymphoma type. The first three represent a continuum of histopathologic changes that range from a hyperplastic infectious mononucleosis-like lesion to a polyclonal mass forming lesion, to a monoclonal lymphoid proliferation that fulfills criteria for one of the B-cell or T/NK-cell lymphomas, as defined in an immunocompetent patient. Plasmactyoma-like PTLD is one of the most uncommon variants and is typified by a late onset (mean 7 years), as opposed to PTLD overall, with highest incidence in the first year following transplant.
  2. The majority of PTLD cases are EBV-driven, and, in fact, EBV seronegativity prior to transplant is one of the major risk factors for developing EBV-associated PTLD.
  3. Other risk factors include the intensity of immunosuppression and type of allograft. PTLD typically presents clinically within lymph nodes, the GI tract, liver, lungs and the allograft itself; initial presentation as a cutaneous nodule is very unusual.1,4

References

  1. Swerdlow SH, Webber SA, Chadburn A, et al. Post-transplant lymphoproliferative disorders. In: Swerdlow SH, Campo E, Harris NL, et al, eds. WHO Classification of Tumours of Hematopoietic and Lymphoid Tissues. Lyon, France: IARC Press; 2008:343-349.
  2. Richendollar BG, His ED, Cook JR. Extramedullary plasmacytoma–like posttransplantation lymphoproliferative disorders: Clinical and pathologic features. Am J Clin Pathol. 2009;132:581-588.
  3. Caillarda S, Lelongb C, Pessioneb F, and Moulin B. Post-transplant lymphoproliferative disorders occurring after renal transplantation in adults: Report of 230 cases from the French registry. Am J Transplantation. 2006; 6: 2735–2742.
  4. Salama S, Todd S, Pietro Cina D, and Margetts P. Cutaneous presentation of post-renal transplant lymphoproliferative disorder: a series of four cases. JCutan Pathol. 2009. E-published ahead of print.
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