Iatrogenic immunodeficiency‑associated lymphoproliferative disorders in transplant and nontransplant settings.

Iatrogenic immunodeficiency‑associated lymphoproliferative disorders comprise a group of lymphoid neoplasms that are associated with an immunosuppressed state, either in the posttransplant period, or during the treatment of various autoimmune and rheumatologic disorders by immunomodulatory medications. Their morphologies vary widely but are generally classified according to the lymphomas that they most closely resemble. This group is strongly associated with infections by the Epstein‑Barr virus as a result of impaired immune function in the immunosuppressed state. Although further classification may become necessary in the coming years, they are distinguished from lymphomas in immunocompetent hosts because reduction or cessation of immunosuppressive or immunomodulatory therapy can result in complete clinical remission.

Novel molecular aberrations and pathologic findings in a tubulocystic variant of renal cell carcinoma.

Tubulocystic renal cell carcinoma (TRCC) is an indolent type of renal cell carcinoma with a good prognosis based on the limited number of published cases. Herein, we describe the unusual clinical, pathologic and molecular fi ndings in a case of TRCC. Our patient with TRCC had two local recurrences and a brain metastasis following radical nephrectomy. Unusual histologic fi ndings included focal solid growth pattern and cytologic atypia. A genome-wide molecular inversion probe assay identifi ed copy number (CN) loss in three chromosome regions and one region with copy-neutral loss of heterozygosity (copy-neutral LOH). Copy number variations (CNVs) were observed (chromosomes 4p16.1 and 17q21.31-q21.32) in both the tumor and the normal tissue, and most likely represents benign variations. The loss of entire chromosomes 9, 18 and 15 and copy-neutral LOH involving 6p22.1 was observed only in the tumor. The presence of these clinical, pathologic and molecular fi ndings could be related to an increased risk for tumor recurrence and poor prognosis. The novel molecular fi ndings described in TRCC might represent new targets for novel therapies.

Uterine mesenchymal tumors.

Uterine mesenchymal tumors are a heterogeneous group of neoplasms that can frequently be diagnostically challenging. Differentiation between the benign and malignant counterparts of mesenchymal tumors is significant due to differences in clinical outcome, and the role of the surgical pathologist in making this distinction (especially in the difficult cases) cannot be underestimated. Although immunohistochemical stains are supportive toward establishing a final diagnosis, the morphologic features trump all the other ancillary techniques for this group of neoplasms. This review therefore emphasizes the key morphologic features required to diagnose and distinguish uterine mesenchymal tumors from their mimics, with a brief description of the relevant immunohistochemical features.