De novo CD5+ diffuse large B-cell lymphomas. A heterogeneous group containing an unusual form of splenic lymphoma

We reviewed our institutional experience with de novo CD5+, large B-cell lymphomas to determine whether they represent a distinct entity and are related to CD5+ small B-cell disorders. We identified 13 cases with multiparameter flow cytometry over a period of 58 months (5% of large B-cell lymphomas) in 7 females and 6 males. Three groups were identified. Group 1 (2 cases) had diffuse splenic red pulp involvement with a distinctive cordal pattern of infiltration, no other clinical evidence of mass disease, microscopic disseminated disease on further workup, and an identical immunoglobulin-negative immunophenotype. Group 2 cases (7 cases) were clinically and morphologically heterogeneous and had an immunophenotype resembling mantle cell lymphoma (FMC7-positive, CD23-). Group 3 (4 cases) had miscellaneous immunophenotypes, including one closely resembling chronic lymphocytic leukemia. Cyclin D1 was positive in only 1 of 10 evaluable cases (group 2). We conclude that CD5+ diffuse large B-cell lymphomas are heterogeneous; most cases do not seem to be related to chronic lymphocytic leukemia or mantle cell lymphoma. However, we identified a subgroup of primary splenic CD5+ large B-cell lymphoma with diffuse red pulp involvement and believe this may represent a distinct clinicopathologic entity.

Primary effusion lymphoma: a distinct clinicopathologic entity associated with the Kaposi's sarcoma-associated herpes virus

We recently discovered the Kaposi's sarcoma-associated herpes virus (KSHV/HHV-8) in an uncommon and unusual subset of AIDS-related lymphomas that grow mainly in the body cavities as lymphomatous effusions without an identifiable contiguous tumor mass. The consistent presence of KSHV and certain other distinctive features of these body cavity-based lymphomas suggest that they represent a distinct entity. We tested this hypothesis by investigating 19 malignant lymphomatous effusions occurring in the absence of a contiguous tumor mass for their clinical, morphologic, immunophenotypic, viral, and molecular characteristics, KSHV was present in 15 of 19 lymphomas. All four KSHV-negative lymphomatous effusions exhibited Burkitt or Burkitt-like morphology and c-myc gene rearrangements and, therefore, appeared to be Burkitt-type lymphomas occurring in the body cavities. In contrast, all 15 KSHV-positive lymphomatous effusions exhibited a distinctive morphology bridging large-cell immunoblastic lymphoma and anaplastic large-cell lymphoma, and all 12 cases studied lacked c-myc gene rearrangements. In addition, these lymphomas occurred in men (15/15), frequently but not exclusively in association with HIV infection (13/15), in which homosexuality was a risk factor (13/13), presented initially as a lymphomatous effusion (14/15), remained localized to the body cavity of origin (13/15), expressed CD45 (15/15) and one or more activation-associated antigens (9/10) in the frequent absence of B-cell-associated antigens (11/15), exhibited clonal immunoglobulin gene rearrangements (13/13), contained Epstein-Barr virus (14/15), and lacked bcl-2, bcl-6, ras and p53 gene alterations (13/15). These findings strongly suggest that the KSHV-positive malignant lymphomatous effusions represent a distinct clinicopathologic and biologic entity and should be distinguished from other malignant lymphomas occurring in the body cavities. Therefore, we recommend that these malignant lymphomas be designated primary effusion lymphomas (PEL), rather than body cavity-based lymphomas, since this term describes them more accurately and avoids their confusion with other malignant lymphomas that occur in the body cavities. We further recommend that these PEL be considered for inclusion as a new entity in the Revised European-American Lymphoma Classification.

Report of a complex karyotype in recurrent metastatic fibrolamellar hepatocellular carcinoma and a review of hepatocellular carcinoma cytogenetics

Metastatic fibrolamellar hepatocellular carcinoma (HCC) was detected in the abdominal lymph nodes of an adolescent male after resection of the primary tumor. No dividing cells were isolated from attempted cytogenetic studies of the primary tumor. However, cytogenetic analysis of lymph node metastases detected 9 and 12 months after partial hepatectomy revealed abnormal hypertriploid karyotypes, with a suggestion of clonal evolution: 62-92 < 3n >,XX, -Y, +3, +6, +6, +7, +7, +8, +10, +13, +15, +16, +20, -21, -22, +mar1 x 2, +mar[cp6]/46,XY[8] and 78 < 3n >,XX, -Y,der(1)t(1;1)(p36.1;q21), +4, +6, +6, +7, +7,i(8)(q10), +10, +15, +20, -21, -22, +mar1 x 2, +mar2[3]/46, XY[17], respectively. Karyotypes of this variant of HCC have not been reported previously. The cytogenetics of HCC are reviewed.

Primary body cavity-based AIDS-related lymphomas

Five patients with advanced AIDS developed a unique type of high grade primary body cavity-based non-Hodgkin's lymphoma (NHL). The lymphomas were exclusively in serous effusions with no detectable mass disease in the body cavities and no lymphadenopathy or organomegaly. All of the lymphomas exhibited virtually identical morphology, which could not be precisely classified, but appeared to bridge features of large cell immunoblastic and anaplastic large cell lymphomas. Immunophenotypically the lymphoma cells lacked expression of any B- or T-lymphocyte antigens, but expressed CD45 and the activation antigens CD30, CD38, CD71, and HLA-DR. Clonally rearranged immunoglobulin heavy chain and kappa light chain genes were identified by Southern blot analysis. Molecular studies also revealed Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) genomes and germline configuration of the c-myc protooncogene. In two cases studied cytogenetically, the lymphoma cells manifested complex chromosome abnormalities. These lymphomas are clinically and biologically unique and found predominantly in patients with advanced AIDS, in many cases with pre-existing Kaposi's sarcoma.

Relapse of precursor B-cell acute lymphoblastic leukemia as an isolated central nervous system mass lesion 9 years after initial diagnosis

Seven years after completion of chemotherapy for acute lymphoblastic leukemia, diagnosed at the age of 5 years, a black female presented with signs of increased intracranial pressure. Neuroimaging showed a large enhancing extra-axial occipital tumor mass. The resection specimen showed morphologic, cytogenetic, and immunophenotypic features consistent with relapse of the primary leukemia. Bone marrow examination was negative for malignancy. The long duration of complete remission followed by the formation of a mass in the central nervous system are highly unusual features of recurrent acute lymphoblastic leukemia.

Flow cytometric terminal deoxynucleotidyltransferase analysis. Evaluation of Triton X-100 and methanol permeabilization methods compared with immunofluorescence microscopy

We evaluated the detection of terminal deoxynucleotidyltransferase by flow cytometry using two commonly reported methods of permeabilization and compared them with immunofluorescence microscopy. Thirty-four consecutive cases referred for leukemia workup were studied prospectively. We found decreased viability of cells with both flow cytometry methods in association with shifts in forward and side scatter patterns. Both procedures demanded careful manipulation of cells to avoid total lysis. The Triton X-100 method had a sensitivity of 100% and a specificity of 93%, while the methanol method had a sensitivity of 54% and a specificity of 100%. Therefore, the Triton X-100 method correlated better with immunofluorescence microscopy than did the methanol method. Despite technical difficulties, the advantages of increased objectivity, increased diagnostic capability associated with multicolor analysis, and the increased sensitivity in detecting minimal residual disease make flow cytometry a more attractive and advantageous procedure.

Non-specific fluorescent whitener stains in the rapid recognition of pulmonary dirofilariasis: a report of 20 cases

BACKGROUND

Solitary lung nodules in humans caused by the dog parasite Dirofilaria immitis are steadily increasing in number. The organisms can be easily missed in haematoxylin and eosin stained tissue when they are degenerated and pale staining.

METHODS

The value of Tinopal CBS-X (TCBS-X) and Calcofluor white (CFW), two rapid, inexpensive, simple non-specific fluorescent whitening stains, were assessed in the identification of these worms. Deparaffinised rehydrated tissue slides prepared from the pulmonary nodules were stained for one minute in 1% w/v aqueous solutions of TCBS-X or CFW, counterstained, coverslipped, and viewed with a fluorescent microscope.

RESULTS

The stains demonstrated the intact worm and worm fragments in 20 cases of pulmonary dirofilariasis collected from hospitals in Houston. The filariae and fragments of filariae stained bright green while the background tissue stained red, delineating the internal structures of the worm.

CONCLUSIONS

Dirofilariasis should be included in the differential diagnosis of subpleural masses, and non-specific fluorescent whitening stains can help in the rapid recognition of the fragmented organism in cytological or surgical material.

New phage typing scheme for Vibrio cholerae O1 biotype El Tor strains

The conventional phage typing scheme proposed by S. Basu and S. Mukerjee (Experientia 24:299-300, 1968) has been used routinely for identification of the strains at the Vibrio Phage Reference Laboratory since 1968. However, because of limitations of this scheme, a new phage typing scheme using five newly isolated phages was incorporated into the conventional scheme. A different definition of routine test dilution (almost confluent lysis) was found to be more useful than the one previously used (confluent lysis). The 1,000 strains tested could be clustered into 27 types with the five new phages. With the new scheme of 10 phages (5 new phages and 5 phages of Basu and Mukerjee), the 1,000 strains could be grouped into 146 types. The new phages were different from each other and also from those of Basu and Mukerjee, as revealed by lytic pattern, electron microscopy, restriction endonuclease digestion, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and antiphage antiserum studies. With the new typing scheme, 99.6% of the strains were typeable. Phage type 115 was the most common and includes 119 (11.9%) of the 1,000 strains tested. Next most common were phage types 142 (9.4%), 143 (7.0%), 104 and 116 (both 5.4%), 3 (5.3%), 5 (4.1%), 4 (3.9%), 24 (2.1%), and 100 (1.7%). The larger number of types would be useful for further classification of the strains for epidemiological purposes. This newly developed scheme is highly applicable to, and could be widely adopted for, phage typing of Vibrio cholerae O1 biotype El Tor strains.

Atypical fibroxanthoma: DNA ploidy analysis of 14 cases with possible histogenetic implications

The histogenesis of atypical fibroxanthoma (AFX) and its relationship to malignant fibrous histiocytoma (MFH) are a subject of controversy. Many investigators have proposed that AFX may represent a reactive process, while others contend that it is a true fibrohistiocytic neoplasm, closely related to MFH. In an attempt to determine whether biologic differences between AFX and MFH may be accounted for at the cellular DNA level, we performed ploidy analysis on 14 cases of AFX by flow cytometry and compared our results with previously reported DNA analyses of MFH. Thirteen of the 14 lesions demonstrated diploid distribution of nuclear DNA, and only 1 case had an aneuploid population. This contrasts with prior data on MFH, the vast majority of which are aneuploid. Our results suggest that, despite histologic similarities, AFX may be distinguished from MFH on the basis of DNA content. These findings may be significant in understanding the biologic behavior of AFX.

Postmortem diagnosis of acute anaphylaxis by serum tryptase analysis. A case report

Systemic anaphylaxis is an acute allergic emergency resulting from generalized mast cell degranulation. In the United States, it is estimated that anaphylaxis accounts for about 500 deaths each year. Hymenoptera-sting hypersensitivity is one of the most common causes of systemic anaphylaxis. The authors report a case of a healthy 26-year-old man who developed acute anaphylaxis after a bee sting, could not be resuscitated, and died within 1 hour. At autopsy, performed 14 hours after the event, the only pathologic findings were laryngeal edema and congestion of lung. Postmortem tryptase levels in the blood were obtained and were instrumental in confirming a diagnosis of acute anaphylaxis. This case is reported to discuss the difficulties associated with using traditional histamine levels in making a diagnosis of anaphylaxis and to validate the value of using tryptase levels to document acute anaphylaxis as a cause of death, even when serum is not obtained until many hours after death.

False aneuploidy in benign tumors with a high lymphocyte content: a study of Warthin's tumor and benign thymoma

The quality of results of flow cytometric DNA content analysis of formalin-fixed, paraffin-embedded tissue may be affected by a number of preanalytical variables. We performed flow cytometric DNA content analysis on two types of benign tumors to investigate the effect of a prominent lymphocytic component: Warthin's tumor (N = 20) and benign thymoma (N = 8). Malignant tumors (N = 23) were included as DNA aneuploid controls. All tissues studied were archival material processed using Hedley's technique either without prolonged rehydration in water (day 0 samples) or with 24- or 48-hour rehydration (day 1 and day 2 samples, respectively). Image cytometric DNA ploidy analysis was also performed on most cases. Eight cases (40%) of Warthin's tumor and five cases (63%) of benign thymoma showed either hyperdiploid peaks or marked asymmetry on the day 0 DNA histograms; nine of the malignant tumors were aneuploid. The DNA histogram abnormalities of the benign tumors could be gated out by excluding the lymphocyte nuclei. None of the DNA indices of the benign tumors corresponded with expected deviations based on published chromosomal studies. All of the DNA histogram abnormalities of the benign tumors disappeared and/or fused with the main peaks on the day 1 or day 2 samples, except for one case of benign thymoma. All the DNA aneuploid peaks on the malignant tumors persisted with prolonged rehydration. Image cytometric DNA analysis showed a diploid pattern in all benign tumors. We conclude that a high lymphocyte content may be a cause of false aneuploidy in these benign tumors. Furthermore, the degree of rehydration appears to be an important factor in achieving optimum fluorochrome staining of DNA.

Heterotopic bone formation in rectal carcinoma. Case report and literature review

A case of heterotopic bone formation in a primary rectal adenocarcinoma was recently observed in a 54-year-old woman. This unusual finding was present both in the diagnostic biopsy and in the subsequently resected bowel. Pertinent gross and microscopic features are presented. This report represents the twelfth case in the literature of heterotopic bone formation in a primary rectal adenocarcinoma and the first such finding in a colonic biopsy from one of these malignancies. The average age of these patients was 56 years (range 32-72) and the male-to-female ratio was 5:7. The rectum is the most common site of ossification in the gastrointestinal tract. The exact mechanism of heterotopic ossification is unknown, but it is probably the result of metaplasia of fibroblasts. Adenocarcinoma has been associated with 12 of the 16 reported cases of rectal glandular tumors with heterotopic bone.

Phage typing of Vibrio cholerae 01 biotype ElT or strains

Data accumulated over the past 20 yr (1969-88) on the phage typing of V. cholerae 01 biotype ElT or strains received at the Vibrio Phage Reference Laboratory, were retrospectively analysed to ascertain the frequency of occurrence of the different phage types of Basu and Mukerjee typing scheme. The analysis revealed that phage types 2 and 4 were the most common types not only at the time when the Basu and Mukerjee typing scheme (of 1968) was introduced but also at present. The existing phage typing scheme needs to be improved with the addition of more new phages to obtain more type distinction and better discrimination within biotype ElT or strains for epidemiological studies.

Brain calcification in hypoxic-ischemic lesions: an autopsy review

Calcification of ischemic lesions in a child's brain is well recognized by pathologists; however, clinicians and radiologists usually associate cerebral calcification with infections, particularly the TORCH organisms. We illustrate this phenomenon in a 5-month-old infant with extensive, calcified, multicystic encephalomalacia without evidence of a cerebral infection. In order to ascertain the incidence of cerebral calcification in pure hypoxic-ischemic lesions, we retrospectively analyzed 486 consecutive autopsies. Ninety-nine patients had histologic evidence of cerebral hypoxic-ischemic lesions and hypoxia or ischemia. Thirty-nine of these patients displayed microscopic calcification; 23 patients had slight, 12 had minor, and 4 had prominent calcifications. Prominent calcification lesions were large enough to be detected by routine radiologic methods. Correlations between degree of calcification and the underlying disease process and between the gestational age and the length of survival were not statistically significant. This study illustrates the very frequent occurrence of brain calcification in ischemic brain lesions in children. It is necessary to include this diagnosis in the differential diagnosis of cerebral calcification.

Isolation and morphological characterization of El Tor cholera phages

Five bacteriophages have been isolated for phage typing of Vibrio cholerae biotype El Tor. The morphology of these phages has been studied by electron microscopy.

Acquired cystic kidney disease: occurrence in patients on chronic peritoneal dialysis

Acquired cystic kidney disease (ACKD) is a well-known complication of long-term hemodialysis. To the best of our knowledge, only six patients on continuous ambulatory peritoneal dialysis have been reported to develop this disease. We herein report two such cases, and concluded that the morphology of ACKD seems to be independent of the type of dialysis and that hemodialysis is not necessary for the development of ACKD.