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We describe the first cases in the literature, to our knowledge, of pruritus as a paraneoplastic symptom of thymoma. The first case is a 36-year-old woman who developed significant generalized pruritus without rash during her second pregnancy, which did not resolve after delivery and which was recalcitrant to topical steroids, antihistamines, and dry skin care. An extensive pruritus laboratory workup was performed and was negative (Table 1). A chest computed tomography (CT) performed 14 months after the onset of pruritus demonstrated a 7.5 × 4.3 cm anterior mediastinal mass that infiltrated the mediastinal fat and abutted the great vessels (Fig. 1A and B; Table 2). CT-guided fine needle aspiration of the mass and a repeat core biopsy was nondiagnostic but consistent with thymic sampling. Immunohistochemistry for Hodgkin's disease (HD) was negative. Based on the very high clinical suspicion of thymoma, she underwent three cycles of neoadjuvant cisplatin, cyclophosphamide, and doxorubicin chemotherapy with good response. Her pruritus resolved 3 days after her first cycle. She had a complete thymectomy, and final pathology demonstrated a Masaoka-Koga stage II World Health Organization type B2 thymoma. The patient is undergoing surveillance, without recurrence of disease or pruritus, now 2 years postoperatively. FIGURE 1 Computed tomography axial views of case 1 demonstrating abutment of proximal great vessels including aorta and pulmonary artery at different planes (A and B). Computed tomography (C) axial view and (D) coronal view of case 2 demonstrating indentation ... TABLE 1 Evaluation of Pruritus TABLE 2 Characteristics of Cases The second case is a 60-year-old woman who presented with 12 months of intermittent generalized pruritus without rash. A pruritus laboratory workup was negative (Table 1). A family history revealed HD in a maternal grandmother. A chest radiograph obtained routinely for work showed an anterior mediastinal mass. CT revealed a 9.2 × 7.7 × 11.7 cm mass, with indentation of the right atrium (Fig. 1C and D; Table 2). CT-guided core biopsy was consistent with thymoma. Clinically, she had a stages I or II thymoma and underwent a complete thymectomy. Final pathology demonstrated a Masaoka-Koga stage I World Health Organization type AB thymoma. Her pruritus resolved immediately after surgery. She is undergoing surveillance, without recurrence of disease or pruritus, now 2 years postoperatively.

A case of T-cell lymphoblastic lymphoma is described in which the patient presented with a characteristic mediastinal mass and lack of bone marrow involvement. Immunologic studies of the surface phenotype of the malignant cells in a pleural effusion with monoclonal antibodies revealed the cells to be of thymic origin and distinguished them from the surface phenotypes seen in T-cell acute lymphoblastic leukemia. Twenty-five months after presentation with lymphoma, the patient developed an acute nonlymphocytic leukemia. With the improved prognosis seen in lymphoblastic lymphoma with intensive combination chemotherapy, it is expected that more cases of subsequent acute nonlymphocytic leukemia will be seen. In view of the natural history of lymphoblastic lymphoma to develop into lymphoblastic leukemia, it is important to be alert to a complicating nonlymphocytic leukemia.

The fate of two recently described human B lymphocyte-specific antigens (B1 and B2) was studied after B-cell activation in vivo and in vitro. Whereas both B1 and B2 were present on virtually all B cells from normal lymph nodes, B2 was absent from approximately 50% of B cells from hyperplastic lymph nodes. When B cells from spleen, tonsil, or peripheral blood were stimulated in vitro with pokeweed mitogen, activated cells were found to lose B2 (days 4-5) and subsequently B1 (days 6-7). Temporally, B2 loss was accompanied by loss of surface IgD, expression of T10, and the development of intracytoplasmic IgM; B1 loss was correlated with the acquisition of surface IgG and the appearance of intracytoplasmic IgG. Peripheral blood B cells, on which B2 is normally only weakly expressed (B1++++B2+) in contrast to B cells from secondary lymphoid organs (B1++++B2++), exhibited a transitory increase in B2 expression to the B1++++B2++ phenotype prior to B2 disappearance during activation. Taken together with other findings, this observation suggests that peripheral blood may contain a relatively immature subpopulation of B cells.

The Ia antigens of the mouse are the basis for the genetic control of the immune response. The HLA-D/DR locus is considered to be the human counterpart of the Ia subregion of the murine major histocompatibility complex1–4. The HLA-D/DR antigens are polymorphic, and eight well defined alleles have been identified using alloantisera5. More recently, ‘supertypic’ antigens (MB and MT) have been defined which identify clusters of HLA-D/DR specificities6–9. Little is known about the molecular basis for the cellular and serological polymorphism of the HLA-D/DR antigens, as alloantisera are usually of very low titre and heteroantisera frequently lack monospecificity. We present here the preparation and characterization of a monoclonal antibody which defines a new polymorphic system of the HLA-D/DR region. This and similar antisera should now begin to provide the reagents with which to correlate molecular structure with the functional repertoire of the human Ia-like antigens.

A monoclonal antibody (anti-B1) specific for a unique B cell surface differentiation antigen was used to characterize the malignant cells from patients with leukemias or lymphomas. All tumor cells from patients with lymphomas or chronic lymphocytic leukemias, bearing either monoclonal kappa lambda light chain, expressed the B1 antigen. In contrast, tumor cells from T cell leukemias and lymphomas or acute myeloblastic leukemia were unreactive. Approximately 50% of acute lymphoblastic leukemias (ALL) of non-T origin and 50% of chronic myelocytic leukemia in blast crisis were also anti-B1 reactive. moreover, 21 of 28 patients with the common ALL antigen (CALLA) positive form of ALL were anti-B1 positive, whereas 0 of 13 patients with CALLA negative ALL were reactive. These observations demonstrate that an antigen present on normal B cells is expressed on the vast majority of B cell lymphomas and on approximately 75% of CALLA positive ALL, suggesting that these tumors may share a common B cell lineage.