Composite lymphoma of Hodgkin lymphoma and mycosis fungoides: previously undescribed in the same extracutaneous site.

Mycosis fungoides (MF), diagnosed and limited to the skin, has been associated with the subsequent development of Hodgkin lymphoma (HL), most commonly of the nodular sclerosing (NS) subtype. In the previously described cases, there are none in which the extracutaneous tissue was simultaneously involved by HL and residual/relapsing MF. Here we report a case of HL, mixed cellularity (MC) subtype, arising in an inguinal lymph node in a patient with a previous diagnosis of MF. We describe the immunophenotypic, histologic and immunohistochemical findings of a composite lymphoma containing the HL, MC subtype and MT. The importance of detecting MF in addition to the HL in the extracutaneous site with available diagnostic modalities is highlighted.

Malignant mesothelioma with CD30-positivity. A case report and review of the literature.

The activation marker CD3O is useful in the diagnosis of Hodgkin and non-Hodgkin lymphomas. It has also been described in nonhematopoietic tumors, including pancreatic carcinomas, salivary gland tumors, and embryonal carcinomas. We report a case of malignant mesothelioma with intense CD30 positivity. This finding has not previously been described and is important in broadening the differential diagnosis of a CD30(+) cohesive large cell malignancy.

CD30+ anaplastic large-cell lymphoma with aberrant expression of CD13: case report and review of the literature.

CD13 is commonly expressed in hematopoietic malignancies of myelomonocytic origin and has less commonly been described in lymphoid neoplasms, including acute lymphoblastic leukemia, B-cell lymphoproliferative disorders, and plasma cell malignancies. Aberrant CD13 expression has rarely been described in KP-1 (CD68)-positive large-cell lymphomas. However, CD13 positivity has not previously been described in a case of CD30+ (ALK-1+) anaplastic large-cell lymphoma of presumed null-cell origin without histiocytic differentiation. The purpose of this case report is to describe a CD30+ anaplastic large-cell lymphoma of presumed null-cell origin with aberrant expression of CD13. The case illustrates the unique usefulness of immunophenotypic and molecular techniques in establishing the correct diagnosis. The case was referred with a diagnosis of "rule out granulocytic sarcoma versus megakaryocytic malignancy" due to the morphology and a limited flow cytometric immunophenotypic (FCI) panel that had been performed and revealed expression of CD45, HLA-DR, and CD13. Subsequent morphologic review at our institution combined with an expanded FCI panel established the diagnosis. The differential diagnosis of a CD13+ hematopoietic malignancy should include this entity. The prognostic significance of this finding has yet to be determined.

T-cell rich, Ki-1-positive post-transplant lymphoproliferative disorder: a previously undescribed variant following liver transplant.

Post-transplant lymphoproliferative disorders (PTLD) are a consequence of the immunosuppressive therapy following organ transplant. We describe a patient who developed PTLD seven years after liver transplant and while receiving cyclosporine and prednisone. Magnetic resonance imaging demonstrated a paraspinal mass extending from T11 to L1. Microscopically, this was composed of a diffuse infiltrate of small to intermediate sized T-lymphocytes with clusters of large anaplastic tumor cells with amphophilic cytoplasm, large irregular nuclei and prominent nucleoli. A high mitotic rate and atypical mitotic figures were noted in the clusters of large cells. Flow cytometric and immunohistochemical analysis failed identify either a monoclonal B-cell population or a T-cell population with aberrant expression of the T-cell surface markers. Strong positivity for CD30 and focal staining for epithelial membrane antigen (EMA) of the large cells was seen. Leukocyte common antigen (LCA), cytokeratin, vimentin, monocyte/macrophage and B- and T-markers were negative. The small lymphoid cells were positive for CD3, MT-1 and UCHL-1. Based on the immunophenotypic and morphological evaluation, this was characterized as a T-cell rich PTLD. PCR analysis identified a monoclonal population of B-cells. This unusual case emphasizes the morphological and immunophenotypic diversity of PTLD. The utility of PCR analysis in the evaluation of PTLD is also demonstrated.