Grading of follicular lymphoma: comparison of routine histology with immunohistochemistry.

Context: Follicular lymphoma (FL) grading is based on the average number of large transformed cells in 10 neoplastic follicles at x40 high-power field (x10-40 high-power field) examination (grade 1, 0-5 centroblasts per high-power field; grade 2, 6-15 centroblasts per high-power field; grade 3, >15 centroblasts per high-power field).

Objective: Since there may be significant interobserver variability, we analyzed the usefulness of immunohistochemical stains in grading FLs more reliably.

Design: Forty-three FLs initially graded by World Health Organization criteria (grade 1, 12; grade 2, 18; grade 3, 13) were reviewed and stained with CD3, CD20, Ki-67, CD30, CD68, PAX-5, and BCL-6.

Bronchiolitis obliterans with organizing pneumonia after rituximab therapy for non-Hodgkin's lymphoma.

Rituximab is a chimeric, anti-CD20 monoclonal antibody initially approved for relapsed, refractory indolent B-cell non-Hodgkin's lymphoma (NHL), and is being applied in an increasing variety of clinical scenarios. Most adverse events are due to an infusion-related symptom complex, and severe pulmonary complications are rare. We describe a case of an NHL patient who received rituximab and developed symptomatic, biopsy-proven multinodular bronchiolitis obliterans with organizing pneumonia (BOOP).

An immunohistochemical evaluation of c-kit (CD-117) expression in malignant melanoma, and results of imatinib mesylate (Gleevec) therapy in three patients.

In order to determine whether imatinib mesylate (Gleevec), a tyrosine kinase inhibitor that binds the CD-117 (c-kit) receptor, may be of value in the treatment of malignant melanoma, an immunohistochemical analysis of 40 cases of primary and metastatic melanoma was undertaken. Thirty-five of the 40 cases showed 1+ or stronger labelling for CD-117 (up to a maximum of 4+). Three patients with neoplasms showing 4+ staining were selected for imatinib therapy.

The faces of mast cell disease: bone marrow infiltrates in 3 patients with systemic mastocytosis.

The clinical spectrum of mast cell disease ranges from relatively innocuous and histologically subtle urticarial skin lesions to an aggressive and fatal leukemic form of mast cell proliferation. Not surprisingly, mast cell infiltrates may show significant microscopic heterogeneity, particularly in the bone marrow, the most common site of involvement in systemic mastocytosis (SM). Herein, 3 cases are presented to illustrate the clinical and morphologic heterogeneity of mast cell disease: the first patient, with long standing urticaria pigmentosa, developed anemia and thrombocytopenia; the second patient presented with a pathologic fracture; and the third patient was suspected to have refractory anemia.

Kaposiform hemangioendothelioma associated with nonimmune fetal hydrops.

We describe the case of a 31-week fetus who died in utero with an invasive retroperitoneal kaposiform hemangioendothelioma. This rare vascular neoplasm usually presents as a localized violaceous skin lesion in infants and behaves in a benign fashion; however, kaposiform hemangioendothelioma may present as an invasive neoplasm of the chest or abdominal cavity, where it can lead to the Kasabach-Merritt syndrome, which consists of thrombocytopenia, consumptive coagulopathy, and microangiopathic anemia in association with a vascular anomaly. The case we describe is unique in that the tumor presented in utero and led to intrauterine nonimmune fetal hydrops.