As cutaneous pilar leiomyomas have received little attention in the recent literature, 53 lesions from 45 patients were studied to analyze their clinicopathologic features. There was an equal distribution between both sexes; most patients were adults with a wide age distribution. Both multiple (29 lesions from 21 patients) and solitary tumors (18 patients) were included. Lesions on the extremity (29 tumors) were common in both groups, whereas truncal tumors (11) were confined largely to patients with multiple lesions. In six patients the number of lesions was not specified. The tumors were painful in 17 patients. Three patients had a positive family history of similar lesions. Histologic study revealed ill-defined bundles of well-differentiated smooth muscle cells in the reticular dermis in all cases, although nine lesions had a more nodular pattern. Overlying epidermal hyperplasia was noted in 29 cases (54.7%). Immunohistochemically there appeared to be an increased number of nerve fibers within and surrounding the tumors. Mitotic activity was observed in 15 lesions (28.3%), 13 of which had <1 mitosis per 10 high power fields (HPF); the remaining two lesions had 1-2 mitoses per 10 HPF. Follow-up was available in 10 of these mitotically active tumors and ranged from 9 months to 7 years. There was no recurrence in any of them. We have concluded tentatively that leiomyomas of arrector pili origin may exhibit a low mitotic activity of <1 per 10 HPF and that this does not adversely affect the prognosis for these patients.

The presence of abundant inflammation is uncommon in well-differentiated liposarcomas (WDLPS). We describe ten cases of WDLPS in which an extensive lymphoplasmacytic infiltrate was present to such a degree that the differential diagnoses included inflammatory pseudotumor and Castleman's disease, and in which the lipogenic component could easily be overlooked. The median age (62 years) and tumor location (six retroperitoneal, three head/neck, one paratesticular) was comparable to usual WDLPS, as was the fact that six of ten cases recurred locally, but none metastasized during the period of follow-up (range 13 to 228 months, median 72 months). Key histologic features included (1) nodular lymphoplasmacytic aggregates; (2) intervening paucicellular stroma containing fibroblastic elements, frequently with plasma cell-rich zones and scattered atypical, often multinucleate cells; (3) merging of atypical adipocytic and inflammatory elements; and (4) adjacent clearly defined zones of lipoma-like or, more rarely, sclerosing-type liposarcoma. In recurrences, two cases "reverted" to purely lipoma-like liposarcoma, and two cases dedifferentiated. Immunoperoxidase studies demonstrated that B cells predominated in the lymphoid aggregates, and that the abundant plasma cells were polytypic in nature. We support the use of the term well-differentiated inflammatory liposarcoma for tumors of this type, which should be distinguished from high-grade liposarcoma containing inflammatory cells, and in order to identify a subgroup of WDLPS at high risk for misdiagnosis.

Chemokine receptors mediate the migration of lymphocytes through the binding of soluble ligands, and their expression is differentially regulated in lymphocyte subsets. The pattern of chemokine receptor expression in T-cell non-Hodgkin lymphoma has not been previously studied. Using a panel of mouse monoclonal antibodies, we studied the immunohistochemical expression of the Th1-associated chemokine receptor CXCR3 in 141 patients with T-cell lymphoma, and we studied the receptors CCR4 and CCR5 and some of their ligands in a subset of these tumors. Expression of CXCR3 was typical of the smaller T cells in angioimmunoblastic lymphoma (15 of 18 patients), angiocentric lymphoma (3 of 3 patients), histiocyte-rich tumors (4 of 5 patients), and unspecified T-cell lymphomas (17 of 39 patients). CXCR3 expression was seen in only 1 of 15 patients with anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma. In contrast, all ALK-positive tumors showed diffuse reactivity for the Th2-associated receptor CCR4 (5 of 5 patients). CCR4 expression was also a consistent feature of the large-cell transformation of mycosis fungoides. CCR5 expression showed no consistent association with any T-cell tumor type. The chemokines Mig (CXCR3 ligand), TARC (CCR4 ligand), and MCP-2 (CCR5 ligand) were detected in intratumoral blood vessels and histiocytes. Mig was also coexpressed by a subset of CXCR3-positive tumor cells in 6 of 20 lymphomas. MCP-2 was highly expressed in stromal cells in 3 patients with nodal involvement by cutaneous T-cell lymphoma. As with normal T-cell subsets, we demonstrated that there is frequent differential expression of chemokine receptors in T-cell tumors, which may explain, in part, the distinctive patterns of spread in different tumor subtypes.

We report 19 unusual cases of mixed tumors and myoepitheliomas arising in soft tissues. The neoplasms occurred in 12 males and seven females. The age at diagnosis ranged from 2 to 83 years (mean 35, median 30). Eight tumors arose in the upper limb, six in the lower limb, three in the trunk, and two in the head and neck region. Three cases involved both dermis and subcutis; the remainder arose in subcutaneous (13 cases) or deep subfascial soft tissue (three cases). The most common presenting complaint was a painless swelling, with duration ranging from 2 weeks to 1 year (median 2.5 months). Microscopically, the tumors were predominantly well circumscribed and lobulated. Six cases showed a focally infiltrative margin. Cardinal morphologic features included nests, cords, and ductules of epithelioid cells and/or nests of spindled cells within a hyalinized to chondromyxoid stroma. One tumor was predominantly composed of myoepithelial cells and devoid of epithelial differentiation (i.e., ductules). Cytoplasmic hyaline inclusions were noted in two cases; squamous differentiation was seen in one case. Osteoid production and/or metaplastic bone was observed in three tumors. Chondroid differentiation (usually mature) was seen in four cases. Adipocytic differentiation was seen in two tumors. Mitotic activity was variable but generally scant; atypical mitotic figures were not identified. By immunohistochemistry, 16 of 16 cases expressed pan-keratin; 16 of 17 S-100 protein; six of 14 alpha smooth muscle actin (IA4); two of 10 muscle specific actin (HHF-35); two of 10 desmin; three of 11 glial fibrillary acidic protein; and three of 16 epithelial membrane antigen. Clinical follow-up was available in 10 patients and ranged from 6 months to 20 years (mean 4.25 years, median 2 years). Two patients developed local recurrence; metastasis to lung and lymph nodes were observed in two additional patients. Both of the latter patients died. We believe that these findings expand the concept of cutaneous mixed tumors to include neoplasms composed predominantly of myoepithelial cells and to include tumors arising in deeper subcutaneous and/or subfascial tissues. The clinical behavior of such neoplasms, when arising in soft tissues, may be difficult to predict but is most often benign; however, a minority of lesions metastasize. Until larger studies with longer follow-up are available, treatment and prognostication are probably best based on criteria used in comparable salivary gland tumors.

Patients with LPHD have different patterns of presentation, sex and age distribution, and likelihood of occult abdominal disease than patients with nodular-sclerosing (NS) or mixed-cellularity (MC) disease. The median time to relapse for LP patients was later than reported for other histologic subtypes; however, there was no pattern of continuous late relapse. With pathologic staging and standard treatment, mortality from LPHD is low; nearly all deaths have been cardiac- or second tumor-related. This suggests that less aggressive treatment for LPHD might continue to yield excellent results, while perhaps lowering the long-term risk of complications.

A major cause of morbidity and mortality following lung transplantation is posttransplant lymphoproliferative disease (PTLD). In a retrospective cohort analysis of pediatric patients, we evaluated the risk factors associated with PTLD in 128 first-time lung transplant recipients from 1990 to 1997. The greatest risk factor for PTLD was a diagnosis of cystic fibrosis (CF). Of the 16 patients in our analysis who had PTLD, 13 had a diagnosis of CF (odds ratio [OR]: 5.8; confidence interval 95% [CI]: 1.6 to 21.4). Because of the high frequency of PTLD in patients with CF (13 of 61; 23%), we performed a retrospective cohort analysis in which patients with CF and PTLD were designated as cases and patients with CF and without PTLD served as controls. In patients with CF, the only risk factor associated with PTLD was two or more episodes of acute rejection within 3 mo after transplantation (OR: 11.0; 95% CI: 2.7 to 55.7). Age, recipient Epstein-Barr virus or cytomegalovirus status, induction with antilymphocyte globulin or antithymocyte globulin (ATG), or use of ATG or OKT3 for acute rejection episodes were not risk factors for PTLD. The high frequency of PTLD in the subgroup of patients with two or more episodes of graft rejection within 2 mo after lung transplantation was unexpected, and warrants further investigation in prospective clinical studies and basic laboratories.

We conclude that the morphologic characteristics of PTLD provide information to potentially help guide treatment strategies in the management of this disease. Standard chemotherapy regimens for malignant lymphoma appear to be a viable treatment option for patients with progressive disease, although further investigation is needed.

This case highlights the fact that a full range of lymphoid proliferations is possible in the posttransplantation period, and that a prior diagnosis of a B-cell disorder does not preclude the development of a subsequent T-cell posttransplant lymphoproliferative disorder (PTLD), which should be formally evaluated, especially if clinical circumstances appear atypical for a PTLD of the "usual" (EBV-related, B-cell) type.