William G. Morice

Distinction of basaloid squamous cell carcinoma from adenoid cystic and small cell undifferentiated carcinoma by immunohistochemistry

Basaloid squamous cell carcinoma (BSCC) is a recently recognized variant of squamous cell carcinoma (SCC) with a predilection to occur in the tongue base, hypopharynx, and supraglottic larynx. In smal biopsy specimens, these tumors can be difficult to distinguish from small cell undifferentiated carcinoma (SCUC) and adenoid cystic carcinoma (ACC). Monoclonal antibodies reactive with cytokeratin (AE1/AE3, 34betaE12, Cam 5.2) as well as a variety of other cellular antigens (vimentin, actin, desmin, chromogranin, synaptophysin, CD57, neuron-specific enolase [NSE], and S100) were used in an immunoperoxidase method with paraffin-embedded tissue to phenotypically characterize 23 cases of BSCC, 10 cases of SCUC, and 15 cases of ACC. The neoplastic cells in 22 of the 23 cases of BSCC reacted with the high-molecular-weight cytokeratin antibody 34betaE12, whereas no reactivity was seen in any of the 10 cases of SCUC. This pattern of 34betaE12 reactivity more consistently differentiated BSCC from SCUC than did reactivity with the neuroendocrine markers chromogranin, synaptophysin, CD57, and NSE. These findings show that immunoperoxidase stains performed on paraffin-embedded tissue are potentially useful in establishing a diagnosis of basaloid squamous cell carcinoma.

Demonstration of aberrant T-cell and natural killer-cell antigen expression in all cases of granular lymphocytic leukaemia

Summary. The diagnosis of granular lymphocytic leukaemia (GLL) requires the presence of an immunophenotypically distinct T‐cell (T‐GLL) or natural killer‐cell (NK‐GLL) population. Flow cytometric immunophenotyping was performed on 21 T‐GLL patients, 11 NK‐GLL patients and 20 normal control subjects using antibodies to T and NK cell‐associated antigens in order to accurately identify the distinguishing features of T‐GLL and NK‐GLL. The NK antigens evaluated included: CD16, CD57, CD94, CD161, and the killing inhibitory receptors (KIRs) CD158a, CD158b and CD158e (p70). Abnormal T‐antigen expression was present in all T‐GLL patients. CD57 was frequently expressed in T‐GLL, however, one‐third of patients showed partial CD57 expression similar to that seen in T cells from normal control subjects. Ten T‐GLL were KIR positive; all expressed a single KIR isoform. All NK‐GLL showed a distinctive, abnormal immunophenotype. Four NK‐GLL expressed a single KIR isoform; the remaining seven patients lacked all tested KIRs, which is also a distinct, abnormal finding. Immunoperoxidase staining of bone marrow biopsy specimens from NK‐GLL patients with antibodies to CD8, TIA‐1 and granzyme B revealed the disease‐specific distinctive staining patterns previously found in T‐GLL. These studies delineate the unique immunophenotypic features diagnostic of T‐GLL and provide strong evidence that NK‐GLL, like T‐GLL, represents a clonal lymphoproliferative disorder.

Overexpression of Syk tyrosine kinase in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are fatal in the majority of patients and novel treatments, such as protein tyrosine kinase (PTK) inhibition, are needed. The recent finding of SYK/ITK translocations in rare PTCLs led us to examine the expression of Syk PTK in 141 PTCLs. Syk was positive by immunohistochemistry (IHC) in 133 PTCLs (94%), whereas normal T cells were negative. Western blot on frozen tissue (n=6) and flow cytometry on cell suspensions (n=4) correlated with IHC results in paraffin. Additionally, western blot demonstrated that Syk-positive PTCLs show tyrosine (525/526) phosphorylation, known to be required for Syk activation. Fluorescence in situ hybridization showed no SYK/ITK translocation in 86 cases. Overexpression of Syk, phosphorylation of its Y525/526 residues and the availability of orally available Syk inhibitors suggest that Syk merits further evaluation as a candidate target for pharmacologic PTK inhibition in patients with PTCL.

Novel immunophenotypic features of marrow lymphoplasmacytic lymphoma and correlation with Waldenström's macroglobulinemia

Lymphoplasmacytic lymphoma involving the bone marrow can be difficult to diagnose, and pathological features that predict the presence of associated Waldenströms macroglobulinemia have yet to be identified. To address these issues, marrow histology, immunohistochemistry, and flow cytometry were studied from 35 lymphoplasmacytic lymphoma cases that had comprehensive clinical assessment for Waldenströms macroglobulinemia. In all cases, the plasma cells were analyzed by a novel 6-color flow method. Both immunohistochemistry and flow cytometry were useful in identifying the lymphoid and plasmacytic disease components. In 19 cases, immunohistochemistry revealed an earlier unrecognized pattern of plasma cell infiltration in which they were physically separate from the lymphoid infiltrates. B-cell flow cytometry revealed monotypic cells in 96% of the cases. Approximately half of these were CD5 and/or CD23 positive, although none had features of chronic lymphocytic leukemia, and none of the B cells had flow cytometric features suggesting plasmacytic differentiation. In contrast, highly sensitive 6-color plasma cell flow cytometry revealed monotypic cells in 32 of the 35 cases; in 20 cases, the pattern of CD38 and CD138 coexpression detected was identical to that seen in plasma cell malignancies such as multiple myeloma. In 18 of these 20 lymphoplasmacytic lymphoma cases, these plasma cells were CD19 positive, distinguishing them from those of true plasma cell neoplasms, which are CD19 negative. It is interesting that the two lymphoplasmacytic lymphoma cases with CD19-negative plasma cells had an IgG isotype serum paraprotein. Apart from this, no other pathological correlates of the clinical or laboratory features of symptomatic Waldenströms macroglobulinemia were identified.

Brief Report: Natural History of Individuals With Clinically Recognized Monoclonal B-Cell Lymphocytosis Compared With Patients With Rai 0 Chronic Lymphocytic Leukemia

PURPOSE The diagnosis of monoclonal B-cell lymphocytosis (MBL) is used to characterize patients with a circulating population of clonal B cells, a total B-cell count of less than 5 x 10(9)/L, and no other features of a B-cell lymphoproliferative disorder including lymphadenopathy/organomegaly. The natural history of clinically identified MBL is unclear. The goal of this study was to explore the outcome of patients with MBL relative to that of individuals with Rai stage 0 chronic lymphocytic leukemia (CLL). PATIENTS AND METHODS We used hematopathology records to identify a cohort of 631 patients with newly diagnosed MBL or Rai stage 0 CLL. Within this cohort, 302 patients had MBL (B-cell counts of 0.02 to 4.99 x 10(9)/L); 94 patients had Rai stage 0 CLL with an absolute lymphocyte count (ALC) < or = 10 x 10(9)/L; and 219 patients had Rai stage 0 CLL with an ALC more than 10 x 10(9)/L. Data on clinical outcome were abstracted from medical records. RESULTS The percentage of MBL patients free of treatment at 1, 2, and 5 years was 99%, 98%, and 93%, respectively. B-cell count as a continuous variable (hazard ratio [HR] = 2.9, P = .04) and CD38 status (HR = 10.8, P = .006) predicted time to treatment (TTT) among MBL patients. The likelihood of treatment for MBL patients was lower (HR = 0.32, P = .04) than that of both Rai stage 0 CLL patients with an ALC less than 10 x 10(9)/L (n = 94) and Rai stage 0 CLL patients with an ALC more than 10 x 10(9)/L (n = 219; P = .0003). CONCLUSION Individuals with MBL identified in clinical practice have a low risk for progression at 5 years. Because B-cell count seems to relate to TTT as a continuous variable, additional studies are needed to determine what B-cell count should be used to distinguish between MBL and CLL.

B-cell count and survival: differentiating chronic lymphocytic leukemia from monoclonal B-cell lymphocytosis based on clinical outcome

The diagnosis of chronic lymphocytic leukemia (CLL) in asymptomatic patients has historically been based on documenting a characteristic lymphocyte clone and the presence of lymphocytosis. There are minimal data regarding which lymphocyte parameter (absolute lymphocyte count [ALC] or B-cell count) and what threshold should be used for diagnosis. We analyzed the relationship of ALC and B-cell count with clinical outcome in 459 patients with a clonal population of CLL phenotype to determine (1) whether the CLL diagnosis should be based on ALC or B-cell count, (2) what lymphocyte threshold should be used for diagnosis, and (3) whether any lymphocyte count has independent prognostic value after accounting for biologic/molecular prognostic markers. B-cell count and ALC had similar value for predicting treatment-free survival (TFS) and overall survival as continuous variables, but as binary factors, a B-cell threshold of 11 x 10(9)/L best predicted survival. B-cell count remained an independent predictor of TFS after controlling for ZAP-70, IGHV, CD38, or fluorescence in situ hybridization (FISH) results (all P < .001). These analyses support basing the diagnosis of CLL on B-cell count and retaining the size of the B-cell count in the diagnostic criteria. Using clinically relevant criteria to distinguish between monoclonal B-cell lymphocytosis (MBL) and CLL could minimize patient distress caused by labeling asymptomatic people at low risk for adverse clinical consequences as having CLL.

Response assessment in Waldenström macroglobulinaemia: update from the VIth International Workshop

This report represents a further update of the consensus panel criteria for the assessment of clinical response in patients with Waldenström macroglobulinaemia (WM). These criteria have been updated in light of further data demonstrating an improvement in categorical responses with new drug regimens as well as acknowledgement of the fact that such responses are predictive of overall outcome. A number of key changes are proposed but challenges do however remain and these include the variability in kinetics of immunoglobulin M (IgM) reduction with different treatment modalities and the apparent discrepancy between IgM and bone marrow/tissue response noted with some regimens. Planned sequential bone marrow assessments are encouraged in clinical trials.

Anti-CD20 monoclonal antibody therapy in multiple myeloma

CD20 is a particularly appealing target that is expressed on the surface of almost all B cells, with no significant shedding, secretion or internalization. In contrast to the demonstrated efficacy of anti‐CD20 strategies in various B‐cell lymphoproliferative disorders, the role of such therapy in multiple myeloma is undetermined and controversial. The expression of CD20 by myeloma cells is heterogeneous, and can be detected only in 13–22% of patients. However, there is increasing interest in testing anti‐CD20 therapy in myeloma because of recent studies suggesting the existence of clonogenic CD20‐positive precursor B cells in the disease. This article reviews the rationale, preclinical and clinical activity of anti‐CD20 therapy in myeloma. Clinical trials show that anti‐CD20 therapy with rituximab elicits a partial response in approximately 10% of CD20+ patients with multiple myeloma. In addition, there is preliminary evidence of disease stabilization in 50–57% of CD20+ patients for a period of 10–27 months. Further large‐scale clinical trials are therefore needed to establish the role of this promising strategy in the treatment of myeloma.

High Levels of Peripheral Blood Circulating Plasma Cells as a Specific Risk Factor for Progression of Smoldering Multiple Myeloma

Smoldering multiple myeloma (SMM) carries a 50% risk of progression to multiple myeloma (MM) or related malignancy within the first 5 years following diagnosis. The goal of this study was to determine if high levels of circulating plasma cells (PCs) are predictive of SMM transformation within the first 2–3 years from diagnosis. Ninety-one patients diagnosed with SMM at Mayo Clinic from January 1994 through January 2007, who had testing for circulating PCs using an immunofluorescent assay and adequate follow-up to ascertain disease progression, were studied. High level of circulating PCs was defined as absolute peripheral blood PCs >5 × 106/l and/or >5% PCs per 100 cytoplasmic immunoglobulin (Ig)-positive peripheral blood mononuclear cells. Patients with high circulating PCs (14 of 91 patients, 15%) were significantly more likely to progress to active disease within 2 years compared with patients without high circulating PCs, 71% versus 24%, respectively, P=0.001. Corresponding rates for progression within 3 years were 86% versus 34%, respectively, P<0.001. Overall survival (OS) after both SMM diagnosis and MM diagnosis was also significantly different. High levels of circulating PCs identify SMM patients with an elevated risk of progression within the first 2–3 years following diagnosis.

Inflammatory pseudotumor of the spleen associated with a clonal Epstein-Barr virus genome: Case report and review of the literature

We report a case of an inflammatory pseudotumor (IPT) of the spleen occurring in an 81-year-old woman with a history of a monoclonal gammopathy of undetermined significance. Eighteen-month follow-up after splenectomy demonstrated no tumor recurrence or progression of underlying plasma cell disease. Histologic examination of the tumor demonstrated a polymorphic population of inflammatory and epithelioid and spindle cells. Immunophenotyping showed large numbers of T cells, B cells, and polyclonal plasma cells. The epithelioid and spindle cells were positive for vimentin and CD68 but lacked expression of follicular dendritic cell markers and actin. Epstein-Barr virus (EBV) genome was identified in the epithelioid and spindle cell population by in situ hybridization using probes specific for EBV-encoded RNAs (EBER1 and EBER2). Southern blot analysis of digested DNA extracted from the tumor using an EBV-specific probe (XhoI) demonstrated the presence of a single high-intensity band, indicative of EBV monoclonality. While there have been 2 previous reports of hepatic IPTs containing a monoclonal population of EBV-infected tumor cells, this is the first report of such an association occurring in the spleen. The presence of clonal EBV DNA suggests some splenic IPTs may be true neoplasms.