Abstract
Casestudy
A 52-year-old female presented with night sweats, chills, anorexia, and weight loss. Computed tomography and positron emission tomography showed a soft tissue infiltration in the anterior mediastinum and hypermetabolic bilateral supraclavicular, mediastinal, right hilar, and left internal mammary lymph nodes. An anterior mediastinal mass resection and thymectomy was subsequently performed.
Results
Sections of the mediastinal mass showed Hodgkin/Reed-Sternberg cells (HRS) admixed with small lymphocytes, histiocytes, plasma cells, and eosinophils. The HRS cells are positive for CD30, CD15, and MUM1, faintly positive for PAX5, and negative for CD20, CD45, CD79a, and BCL6. The morphology and immunophenotype is diagnostic of nodular sclerosis classic Hodgkin lymphoma (CHL). Sections of the thymectomy specimen showed similar morphology, however, in an area that represents 10-20% of the specimen, there are nodular and diffuse lymphoid infiltrates consisting of small lymphocytes, histiocytes, and large atypical cells. The large atypical cells are positive for CD20, CD23, CD30, CD45, CD79a, BCL2, BCL6, MUM-1, and PAX5, and negative for CD1a, CD3, CD57, and Cyclin D1. The background small CD3-positive lymphocytes form a rosette around most of the large atypical cells. CD21 and CD23 stains highlight residual follicular structures. In situ hybridization for EBV-encoded RNA (EBER) is negative. The presence of residual follicular meshwork with an immunophenotype of large B cell lymphoma supports a diagnosis of a gray zone lymphoma (GZL). Overall, CHL is involving 80-90% and GZL is involving 10-20% of the thymic tissue. The patient was subsequently placed on ABVD chemotherapy and achieved remission.
Conclusion
An accurate diagnosis of GZL is challenging. GZL is a rare type of lymphoma with morphological features between CHL and diffuse large B-cell lymphoma (DLBCL). It is even rarer to encounter a CHL concurrently present with a GZL. The optimal therapeutic approach for cases with concurrent lymphoma diagnosed with CHL and GZL needs further investigation.
Gray Zone Lymphoma: Better Treated Like Hodgkin Lymphoma or Mediastinal Large B-Cell Lymphoma?