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Notes: Background:  Criteria for distinguishing between cutaneous lymphoid hyperplasia (CLH) and low-grade B-cell lymphoma are not well defined. We examined the hypothesis that the presence of a clonal B-cell population in heavy multinodular lymphoid infiltrates correlates with clinical presentation and outcome.Methods:  We identified 29 patients with skin lesions characterized histologically by a heavy dermal lymphocytic infiltrate with a multinodular architecture and extension into deep dermis and subcutaneous fat. Clonality was assessed immunophenotypically by light-chain restriction and also by analysis for IgH-gene rearrangement using PCR on DNA extracted from paraffin blocks.Results:  Follow-up (mean 80 months; median 45 months) was obtained in all patients. Twenty-four patients (83%) presented with a solitary lesion: only four had solitary recurrences, and none developed multiple synchronous lesions or systemic B-cell lymphoma. However, 9/24 of these solitary lesions (38%) were clonal by light-chain restriction or IgH PCR; 5/29 patients (17%) presented with multiple recurrent lesions and continued to develop lesions during the period of follow-up; 3/5 patients (60%) with multiple lesions demonstrated a B-cell clone. No patient developed systemic B-cell lymphoma.Conclusions:  Heavy, multinodular cutaneous lymphoid infiltrates have an excellent prognosis. Multiple lesions at presentation are the best predictor of recurrent multiple lesions confined to the skin. The presence of a clonal B-cell population does not correlate with clinical presentation or histology, nor does it predict development of further lesions or systemic lymphoma.

Notes: Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases Neoplasms of histiocytes and dendritic cells are rare, and their phenotypic and biological definition is incomplete. Seeking to identify antigens detectable in paraffin-embedded sections that might allow a more complete, rational immunophenotypic classification of histiocytic/dendritic cell neoplasms, the International Lymphoma Study Group (ILSG) stained 61 tumours of suspected histiocytic/dendritic cell type with a panel of 15 antibodies including those reactive with histiocytes (CD68, lysozyme (LYS)), Langerhans cells (CD1a), follicular dendritic cells (FDC: CD21, CD35) and S100 protein. This analysis revealed that 57 cases (93%) fit into four major immunophenotypic groups (one histiocytic and three dendritic cell types) utilizing six markers: CD68, LYS, CD1a, S100, CD21, and CD35. The four (7%) unclassified cases were further classifiable into the above four groups using additional morphological and ultrastructural features. The four groups then included: (i) histiocytic sarcoma (n=18) with the following phenotype: CD68 (100%), LYS (94%), CD1a (0%), S100 (33%), CD21/35 (0%). The median age was 46 years. Presentation was predominantly extranodal (72%) with high mortality (58% dead of disease (DOD)). Three had systemic involvement consistent with `malignant histiocytosis'; (ii) Langerhans cell tumour (LCT) (n=26) which expressed: CD68 (96%), LYS (42%), CD1a (100%), S100 (100%), CD21/35 (0%). There were two morphological variants: cytologically typical (n=17) designated LCT; and cytologically malignant (n=9) designated Langerhans cell sarcoma (LCS). The LCS were often not easily recognized morphologically as LC-derived, but were diagnosed based on CD1a staining. LCT and LCS differed in median age (33 versus 41 years), male:female ratio (3.7:1 versus 1:2), and death rate (31% versus 50% DOD). Four LCT patients had systemic involvement typical of Letterer–Siwe disease; (iii) follicular dendritic cell tumour/sarcoma (FDCT) (n=13) which expressed: CD68 (54%), LYS (8%), CD1a (0%), S100 (16%), FDC markers CD21/35 (100%), EMA (40%). These patients were adults (median age 65 years) with predominantly localized nodal disease (75%) and low mortality (9% DOD); (iv) interdigitating dendritic cell tumour/sarcoma (IDCT) (n=4) which expressed: CD68 (50%), LYS (25%), CD1a (0%), S100 (100%), CD21/35 (0%). The patients were adults (median 71 years) with localized nodal disease (75%) without mortality (0% DOD). In conclusion, definitive immunophenotypic classification of histiocytic and accessory cell neoplasms into four categories was possible in 93% of the cases using six antigens detected in paraffin-embedded sections. Exceptional cases (7%) were resolvable when added morphological and ultrastructural features were considered. We propose a classification combining immunophenotype and morphology with five categories, including Langerhans cell sarcoma. This simplified scheme is practical for everyday diagnostic use and should provide a framework for additional investigation of these unusual neoplasms.

Notes: Abstract Background:Allogeneic bone marrow transplantation (BMT) has beenused in patients with low-grade lymphoma (LGL) and chronic lymphocyticleukemia (CLL) with the goal of achieving long-term disease-free survival. Patients and methods:Twenty-nine patients with these diagnoses(LGL = 19, CLL = 10) received allogeneic BMT between September 1995 andJanuary 1999. Median age was 42 (range 20–52) years. Twenty-three oftwenty-nine patients (79%) were Ann Arbor or Rai stage IV at the timeof transplant; twenty-four (83%) had never achieved complete remission(CR). Donor source was HLA-matched sibling (20), unrelated (8) and syngeneic(1). Results:Seventeen patients are currently alive, a median of 29months (range 1–85) post-BMT with a median KPS of 90%.Twenty-three of twenty-seven evaluable patients (85%) achieved CRpost-BMT. Six patients had refractory/recurrent disease. Death occurredrelated to transplant complications in eight patients and underlying diseasein four. Overall and event-free survival for the whole group is 51% and44%, respectively. Conclusions:Allogeneic BMT for young patients with advanced stageLGL or CLL is a feasible strategy that can result in achievement of long-termdisease-free survival.