Anaplastic large cell lymphoma (ALCL) is a distinct type of T/null-cell non-Hodgkin lymphoma that commonly involves nodal and extranodal sites. The World Health Organization of lymphoid neoplasms recognizes two types: anaplastic lymphoma kinase (ALK) positive or ALK negative, the former as a result of abnormalities involving the ALK gene at chromosome 2p23. Patients with ALCL rarely develop a leukemic phase of disease, either at the time of initial presentation or during the clinical course. Described herein is a patient with ALK+ ALCL, small cell variant, associated with the t(2;5)(p23;q35), who initially presented with leukemic involvement and an extraordinarily high leukocyte count of 529 x 10(9)/L, which subsequently peaked at 587 x 10(9)/L. Despite chemotherapy the patient died 2(1/2) months after diagnosis. In the literature review 20 well-documented cases are identified of ALCL in leukemic phase reported previously, with a WBC ranging from 15 to 151 x 10(9)/L. Leukemic phase of ALCL occurs almost exclusively in patients with ALK+ ALCL, most often associated with the small cell variant and the t(2;5)(p23;q35), similar to the present case. Patients with leukemic phase ALK+ ALCL appear to have a poorer prognosis than most patients with ALK+ ALCL.

T-cell prolymphocytic leukemia (T-PLL) can involve extramedullary sites, but the diagnosis is usually established by examination of blood and bone marrow. As a result, the histologic findings at extramedullary sites are poorly documented in the literature. We describe 19 extramedullary biopsy specimens from 14 patients with T-PLL. Skin (n = 10) was the most common site biopsied. T-PLL surrounded dermal blood vessels and appendages (n = 6), diffusely replaced dermis (n = 3), or formed a subcutaneous mass (n = 1). Other extramedullary sites included liver and lymph nodes (3 each) and spleen, lung, and cecum (1 each). In liver and lymph nodes, the neoplasm predominantly involved portal tracts and paracortex, respectively. Cytologically, the T-PLL cells were round (n = 16) or Sezary cell-like (n = 3). Nucleoli were observed in a subset of cells in 8 specimens and were prominent in 3 specimens. Immunostaining for T-cell leukemia-1 (TCL-1) was positive in specimens from 9 (64%) of 14 patients. We conclude that the prolymphocytoid features of T-PLL cells can be difficult to detect in routinely stained sections of extramedullary biopsy specimens. TCL-1 expression can aid in diagnosis at extramedullary sites.

Most human cases of West Nile virus infection are acquired via bites from an infected mosquito. In some cases, infection may also be transmitted by infected blood products or transplanted organs. There have been recent publications suggesting that chemotherapy and immunosuppression may increase a person's risks of developing central nervous system disease if the person is infected with the West Nile virus. Because patients undergoing hematopoietic stem cell transplantation not only are immunocompromised, but also receive multiple blood products, they are at a particularly high risk for acquiring symptomatic disease if exposed to the West Nile Virus. We describe here 2 patients who underwent hematopoietic transplantation at our institution and subsequently developed fatal West Nile virus infections.

Two cases of Langerhans cell histiocytosis involving the vulva are reported. The clinical features of Case 1 have been previously reported. The patients, aged 31 (Case 1) and 52 (Case 2) years, had disease limited to the vulva at the time of diagnosis. In both cases, the vulvar lesions were composed of Langerhans cells with twisted nuclei and nuclear grooves, associated with eosinophils and other inflammatory cells. Immunohistochemical studies using fixed, paraffin-embedded tissue sections showed that the Langerhans cells were positive for CD1A and S-100 protein in both cases, supporting the morphologic diagnosis. The first patient had multiple local recurrences during 3 years despite radiation therapy and vulvectomy, but is currently in remission and being treated with thalidomide. The second patient experienced disseminated disease involving multiple bony sites and the mouth despite radiation therapy. Including the present two cases, 6 of 18 (33%) cases of isolated vulvar LCH subsequently disseminated, most commonly to bone; other patients had local recurrences. Thus isolated vulvar LCH has the potential for aggressive clinical behavior, either as local recurrence or disseminated disease. New treatment modalities are needed for this disease.