[Plasma cell myeloma in the stomach?]. / Plasmazellmyelom im Magen?

The detection of a diffuse infiltrate of heterogeneous small B-cells in the lamina propria mucosae invading the epithelium and destroying the glandular tissue by discrete aggregates of three or more marginal zone B-cells above the basal membrane (so-called lymphoepithelial lesions) is suspicious of a mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach. The demonstration of a monoclonal B-cell population by immunohistochemistry, in situ hybridization or PCR excludes a benign lymphatic lesion. In the differential diagnosis with other small B-cell lymphomas in the stomach, a panel of five different immunohistochemical markers is useful to diagnose a small lymphocytic lymphoma (CD5 and CD23 positive), a mantle cell lymphoma (CD5 and cyclin D1 positive) or a follicular lymphoma (BCL2 and CD10 positive). The presence of the translocation t(11;18)(q21;q21) or the API2/MALT1 rearrangement could give further information about the clinical course and the prognosis of a gastric MALT lymphoma.

Is there a role for capsule endoscopy in the staging work-up of patients with gastric marginal zone B-cell lymphoma of MALT?

INTRODUCTION: In earlier studies, involvement of the small intestine was reported in patients with gastrointestinal lymphoma. Prospective data on the involvement of the small intestine in patients suffering from gastric extranodal MZBCL of MALT do not exist so far. In this study, we investigated the frequency of the involvement of the small intestine and the role of capsule endoscopy in patients with gastrointestinal extranodal MZBCL of MALT and of follicular lymphoma. PATIENTS AND METHODS: 40 consecutive patients with gastrointestinal extranodal MZBCL of MALT (26 men, 14 women, aged 27 - 80 years), and 7 patients with known follicular lymphoma of the small intestine (5 men, 2 women, aged 34 - 63 years) underwent capsule endoscopy. RESULTS: Involvement of the small intestine was identified by capsule endoscopy in all 7 patients with known follicular lymphoma of the small intestine. In 6 of 40 patients with gastric extranodal MZBCL of MALT abnormal findings could be observed, three of these findings indicative for lymphoma involvement of the small intestine. However, in each of these 3 cases, intestinal involvement had been already diagnosed by conventional GI endoscopy before capsule endoscopy. CONCLUSIONS: Capsule endoscopy is able to detect involvement of the small intestine in patients with gastrointestinal lymphoma. However, involvement of the small intestine seems to be rare in patients with gastric extranodal MZBCL of MALT. In summary, routine diagnostic work-up of the small intestine, e. g. by capsule endoscopy seems unnecessary because of the rare involvement of the small intestine and an excellent long-term outcome irrespective of a possible intestinal manifestation.

[Polypoid dysplasia in inflammatory bowel disease: differential diagnosis and further diagnostic and therapeutic approaches]. / Polypoide Dysplasie bei chronisch-entzündlicher Darmerkrankung: Differenzialdiagnose und weiteres diagnostisch-therapeutisches Vorgehen.

Polypoid dysplasia in inflammatory bowel disease (IBD) is categorized as DALM (dysplasia associated lesion or mass) or ALM (adenoma-like mass). DALMs are etiologically related to the underlying inflammatory disease, have a high risk of cancer and remain an indication for colectomy. Sporadic adenomas occur coincidentally according to the adenoma-carcinoma sequence. They are adequately treated by polypectomy. More recently, a special group of lesions has been termed as "adenoma-like DALM" which shows a morphological overlap with sporadic adenomas in spite of arising against the background of chronic IBD. Adenoma-like DALMs may possess a lower risk of malignancy in contrast to non-adenoma-like DALMs. They may be treated adequately by polypectomy and continued monitoring if the lesion has been excised completely and there is no evidence of flat dysplasia elsewhere in the colon.

[Microscopic colitis: histopathological review with a clinicopathological correlation]. / Mikroskopische Kolitis: Histopathologische Übersicht mit klinisch-pathologischer Korrelation.

Microscopic colitis is a clinicopathological entity which, in addition to typical symptoms such as watery diarrhea, is characterized by its specific histopathology. Since colonoscopy yields normal findings, microscopic colitis belongs in a histological domain. The term encompasses two forms: lymphocytic and collagenous colitis. Histologically, lymphocytic colitis shows an increase in intraepithelial lymphocytes of more than 20 lymphocytes per 100 surface colonocytes, while collagenous colitis is characterized by a thickened subepithelial collagen layer of more than 10 µm. Specific stains help in the quantification of both. Since microscopic colitis does not always affect the entire colon and the number of intraepithelial lymphocytes varies physiologically, obtaining stepwise biopsies of the colon (with information on location where possible) is recommended. A thickened collagen layer is relatively specific for collagenous colitis, whereas intraepithelial lymphocytosis is also found in other diseases. Therefore, to make a correct diagnosis, it is important to correlate histological findings with clinical symptoms, including the main symptom of watery diarrhea.

Detailed mapping of chromosome 17p deletions reveals HIC1 as a novel tumor suppressor gene candidate telomeric to TP53 in diffuse large B-cell lymphoma.

Deletions in the short arm of chromosome 17 (17p) involving the tumor suppressor TP53 occur in up to 20% of diffuse large B-cell lymphomas (DLBCLs). Although inactivation of both alleles of a tumor suppressor gene is usually required for tumor development, the overlap between TP53 deletions and mutations is poorly understood in DLBCLs, suggesting the possible existence of additional tumor suppressor genes in 17p. Using a bacterial artificial chromosome (BAC) and Phage 1 artificial chromosome (PAC) contig, we here define a minimally deleted region in DLBCLs encompassing approximately 0.8 MB telomeric to the TP53 locus. This genomic region harbors the tumor suppressor Hypermethylated in Cancer 1 (HIC1). Methylation-specific PCR demonstrated hypermethylation of HIC1 exon 1a in a substantial subset of DLBCLs, which is accompanied by simultaneous HIC1 deletion of the second allele in 90% of cases. In contrast, HIC1 inactivation by hypermethylation was rarely encountered in DLBCLs without concomitant loss of the second allele. DLBCL patients with complete inactivation of both HIC1 and TP53 may be characterized by an even inferior clinical course than patients with inactivation of TP53 alone, suggesting a functional cooperation between these two proteins. These findings strongly imply HIC1 as a novel tumor suppressor in a subset of DLBCLs.

Centrosome aberrations as a possible mechanism for chromosomal instability in non-Hodgkin's lymphoma.

Recently, centrosome aberrations have been described as a possible cause of aneuploidy in many solid tumors. To investigate whether centrosome aberrations occur in non-Hodgkin's lymphoma (NHL) and correlate with histologic subtype, karyotype, and other biological disease features, we examined 24 follicular lymphomas (FL), 18 diffuse large-B-cell lymphomas (DLCL), 33 mantle cell lymphomas (MCL), and 17 extranodal marginal zone B-cell lymphomas (MZBCL), using antibodies to centrosomal proteins. All 92 NHL displayed numerical and structural centrosome aberrations as compared to nonmalignant lymphoid tissue. Centrosome abnormalities were detectable in 32.3% of the cells in NHL, but in only 5.5% of lymphoid cells from 30 control individuals (P<0.0001). Indolent FL and MZBCL contained only 25.8 and 28.8% cells with abnormal centrosomes. In contrast, aggressive DLCL and MCL harbored centrosome aberrations in 41.8 and 35.0% of the cells, respectively (P<0.0001). Centrosomal aberrations correlated to lymphoma grade, mitotic, and proliferation indices, but not to the p53 labeling index. Importantly, diploid MCL contained 31.2% cells with abnormal centrosomes, while tetraploid samples harbored centrosome aberrations in 55.6% of the cells (P<0.0001). These results indicate that centrosome defects are common in NHL and suggest that they may contribute to the acquisition of chromosomal instability typically seen in NHL.

Immunohistochemical analysis of B-cell lymphoma using tissue microarrays identifies particular phenotypic profiles of B-cell lymphomas.

AIMS: To validate the applicability of tissue microarray (TM) in immunohistochemical profiling of B-cell lymphoma and to identify particular phenotypic profiles of B-cell neoplasms. METHODS AND RESULTS: Eighty-two diffuse large B-cell lymphomas (DLBL), 54 follicular lymphomas (FL) and 74 mantle cell lymphomas (MCL) were arrayed. Immunohistochemical stains of TM were compared with immunostains of conventional, formalin-fixed and frozen material sections. Concordant staining results were obtained in more than 88% of cases for CD20, CD3, CD5, CD10, CD23, Bcl-2, IgD, secretory differentiation, p53 and p21 expression. Prognostically relevant hot-spot expression of Ki67 yielded concordant results in 71%. Applying TM for characterization of p27KIP1 expression, both typical and blastoid MCL only rarely showed p27KIP1 expression (9% and 15%), whereas 32% of nodal DLBL were p27KIP1-positive, irrespective of high proliferative activity. Among 22 B-cell lymphomas investigated genetically, a p53 + p21- immunophenotype in >20% of tumour cells correlated with p53 locus deletion. CONCLUSIONS: Lymphoma TM allows for immunohistochemical profiling of human B-cell lymphoma with a comparable accuracy to immunohistochemical studies performed on conventional tissue sections. Nodal DLBLs showed significantly more frequent expression of IgD and p27KIP1 than extranodal DLBL. MCL and DLBL frequently showed aberrant p27KIP1 expression. A p53 + p21- immunophenotype in >20% of tumour cells in B-cell non-Hodgkin's lymphoma correlates with p53 gene deletion.

Recurrent genetic aberrations in thymoma and thymic carcinoma.

Apart from single reported aberrant karyotypes, genetic alterations in thymic epithelial neoplasms have not been investigated so far. In this study, 12 World Health Organization classification type A thymomas (medullary thymomas), 16 type B3 thymomas (well-differentiated thymic carcinomas), and nine type C thymomas, all of them primary thymic squamous cell carcinomas, were analyzed by comparative genomic hybridization and fluorescence in situ hybridization. With the exception of one single case, type A thymomas did not reveal chromosomal gains or losses in comparative genomic hybridization. In contrast, all type B3 thymomas showed chromosomal imbalances, with gain of 1q, loss of chromosome 6, and loss of 13q occurring in 11 (69%), six (38%), and five (31%) of 16 cases, respectively. In primary thymic squamous cell carcinoma, the most frequent chromosomal losses were observed for 16q (six of nine cases, 67%), 6 (4 of 9, 44%), and 3p and 17p (three of nine each, 33%), whereas recurrent gains of chromosomal material were gains of 1q (5 of 9, 56%), 17q, and 18 (three of nine each, 33%). This study shows that the distinct histological thymoma types A and B3 exhibit distinct genetic phenotypes, whereas type B3 thymoma and primary thymic squamous cell carcinoma partially share genetic aberrations. In addition to the possible tumorigenic role, the deletion in type B3 thymoma of chromosome 6, harboring the HLA locus, might play a role in the pathogenesis of paraneoplastic autoimmunity characteristic of thymoma.

Marginal zone B-cell lymphomas (MZBL) arising at different sites represent different biological entities.

Most entities of B-cell malignant non-Hodgkin's lymphomas (NHL) are characterized by typical primary chromosomal changes such as the t(14;18) in follicular lymphoma or the t(11;14) in mantle cell lymphoma. In contrast, marginal zone B-cell lymphomas (MZBL), arising at different nodal and extranodal sites, are poorly characterized on the genetic level. We performed cytogenetic investigations in 20 splenic and in 10 nodal MZBL and analyzed 52 MZBL (including 12 MALT-type lymphomas) for deletions of TP53, D13S25, and RB1 loci by fluorescence in situ hybridization. A new nonrandom chromosomal aberration, del(10)(q22q24), was found as a clonal anomaly in 3 out of 20 cases of splenic MZBL. Further recurring abnormalities such as del(7q) or trisomy 3 were found to be characteristic chromosomal changes in a subset of splenic MZBL. TP53 was deleted in 5/25 cases of splenic MZBL. Deletions involving band 13q14 were only rarely encountered, challenging a previous report that stated a dissociated D13S25-RB1 status as characteristic in splenic MZBL. There are fundamental differences between the different subtypes of marginal zone lymphomas as defined with current classification schemes. Splenic MZBL, in contrast to most other entities of B-cell NHL, seems to constitute a heterogeneous disease especially with regard to genetic alterations. del(10)(q22q24) could be of importance at least in a subset of this lymphoma entity.

Genetic imbalances in primary gastric diffuse large B-cell lymphomas: comparison of comparative genomic hybridization, microsatellite, and cytogenetic analysis.

Extranodal malignant non-Hodgkin's lymphomas account for about 40% of lymphoid neoplasms, but few data are available concerning the genetic background of primary gastric diffuse large B-cell lymphoma (DLBCL). A study was performed of 27 primary gastric DLBCLs and 5 gastric DLBCLs with a concomitant low grade component of mucosa-associated lymphoid tissue-type lymphoma using comparative genomic hybridization (CGH), microsatellite studies, classic cytogenetics, and fluorescence in situ hybridization (FISH) to search for specific genetic aberrations. The most frequent aberrations were losses of material on chromosome 6q and gains of parts of chromosome 3. In three cases, a total of six high level DNA amplifications were detected, with five of them involving chromosomal regions not having been reported before in gastric DLBCL. A high overall concordance of 91.4% between microsatellite analysis and CGH was observed using DNA extracted from the same tissue block. The concordance achieved using DNA from different tissue blocks of the same patient was 85%. Microsatellite studies, CGH, FISH, and classic cytogenetics represent complementary techniques that facilitate a comprehensive view of genetic alterations in malignancies such as primary gastric DLBCL.

[Genetic and biological features define two types of follicular non-Hodgkin grade 3 lymphoma]. / Genetische und biologische Unterschiede definieren zwei Varianten follikulärer Non-Hodgkin-Lymphome Grad 3.

In the REAL classification system, follicular lymphomas (FL) were subdivided into three grades depending on the number of blasts (6). In this study, we were interested in defining biological parameters possibly being important in the delineation of subgroups. Between 1990 and 1998, biological and cytogenetic investigations were performed on 91 FL. Clonal aberrations were found in all cases. The tumours were subclassified according to the blast content and the morphology of the centrocytes into 29 FL 1, 33 FL 2, 15 FL 3, and 14 FL 3 with a diffuse large B-cell lymphoma component (FL 3 + DLBL). They were characterised by classical cytogenetics, for their mitotic (MI) and proliferative (PI) indices, and CD10, bcl-2, and p53-expression. In contrast to FL 1 and FL 2, which showed a common genetic background with t(14;18), and only differed by their blast content and MI/PI, FL 3 (with or without associated DLBL) turned out to be an inhomogeneous group. 11 follicular lymphomas (with > 150 blasts/10HPF) still showed maturation to centrocytes. They were positive for CD10 and harboured the t(14;18) in 73%. These cases correspond to a "high grade" variant of centroblastic-centrocytic lymphoma according to the Kiel classification (FL 3a). In 18 cases with a follicular or follicular and diffuse growth pattern, the infiltrate consisted of centroblasts exclusively. These tumours were CD10+ in only 50% and were t(14;18)+ in only 22%. Secretory differentiation (clg+) was found in 44%. They were--with respect to primary and secondary chromosome aberrations--more comparable to a follicular variant of DLBL and hence, correspond to centroblastic lymphoma, follicular or centroblastic lymphoma, follicular and diffuse according to the Kiel classification (FL 3b). By histomorphological, biological and cytogenetic investigations, therefore, FL 3 can be delineated into two different biological subgroups with obviously different transformation pathways.

Exclusive detection of the t(11;18)(q21;q21) in extranodal marginal zone B cell lymphomas (MZBL) of MALT type in contrast to other MZBL and extranodal large B cell lymphomas.

Extranodal mucosa-associated lymphoid tissue (MALT)-type lymphomas and nodal and splenic marginal zone B cell lymphomas (MZBL) share morphological and immunophenotypic features with marginal zone B cells of reactive lymphoid tissues. Although displaying a similar immunophenotype, recent investigations suggest fundamental genetic differences among these subgroups. To determine the prevalence of the t(11;18) in a larger series of MALT-type lymphomas and to investigate a possible occurrence in other lymphomas, we screened 106 non-Hodgkin's lymphomas (NHL) by interphase cytogenetics using yeast artificial chromosome (YAC) probes flanking the breakpoint at 11q21. A signal constellation indicating a disruption in 11q21 and thus pointing to the presence of the t(11;18) was observed in 9 of 33 (27%) low-grade lymphomas of MALT type. The complete absence of t(11;18)-positive cells in 32 primary and secondary extranodal high-grade lymphomas suggests that low-grade lymphomas of MALT type characterized by the t(11;18) are unlikely to transform into high-grade tumors. The absence of tumor cells carrying the t(11;18) in nodal MZBL challenges the assumption that most, if not all, of these tumors represent the nodal manifestation of a so far undetected low-grade lymphoma of MALT type. The t(11;18) was not detected in a single case of 29 splenic MZBL investigated. This observation strengthens the view that splenic MZBL are biologically different from extranodal MZBL of MALT type.

A biological role for deletions in chromosomal band 13q14 in mantle cell and peripheral t-cell lymphomas?

Structural aberrations of chromosomal band 13q14 are frequent in B-cell chronic lymphocytic leukemia (B-CLL) and target a putative tumor suppressor gene in the genomic region between the RB1 gene and the genetic marker D13S25. Recently, it has been suggested that alterations of this particular region might also be of relevance for the pathogenesis of mantle cell lymphomas (MCL). We applied dual-color fluorescence in situ hybridization (FISH) using probes for the RB1 and/or D13S25 loci and screened a total of 236 B- and T-cell non-Hodgkin's lymphomas (NHL) for deletions occurring in this genomic region. In MCL, the high rate (12/32; 38%) of hemizygous deletions and especially a deletion pattern similar to B-CLL in four of the cases provide further evidence that a substantial proportion of MCL cases may share a common way of pathogenesis with B-CLL. In other B-cell NHL, the frequency of allelic loss affecting 13q14 was overall low. However, the finding of 13q14 microdeletions in seven cases without detectable alterations of chromosome 13 at G-banding analysis might indicate a possible involvement of this genetic region also for the lymphomagenesis of single cases of B-cell NHL other than B-CLL and MCL. In T-cell NHL, allelic loss at 13q14 was encountered in three of 13 peripheral T-NHL, NOS. Taking into account the very limited cytogenetic data yet available in this entity, our series provides further evidence that 13q14 changes might represent one of the most frequent genetic abnormalities in T-cell NHL.

t(1;2)(q21;p23) and t(2;3)(p23;q21): two novel variant translocations of the t(2;5)(p23;q35) in anaplastic large cell lymphoma.

Cytogenetic investigations in two cases of anaplastic large cell lymphoma (ALCL) showed novel variants of the classical (2;5)(p23;q35) translocation, namely a t(1;2)(q21;p23) and a t(2;3)(p23;q21). The tumor cells in both cases gave positive immunohistochemical labeling for ALK protein (with both monoclonal and polyclonal antibodies), demonstrating that these translocations induce aberrant expression of this kinase and suggesting that genes other than NPM can activate the ALK gene in ALCL. These two cases were shown by an in vitro kinase assay to express ALK kinases (104 kD and 97 kD, respectively), which differed in size from the classical NPM-ALK fusion product (80 kD). Moreover, ALK expression was confined to the cytoplasm of the tumor cells in each case, supporting the hypothesis that the observed nuclear localization of NPM-ALK in classical ALCL is not the site of oncogenic activity of the ALK kinase.

ICP measurement accuracy: the effect of temperature drift. Design of a laboratory test for assessment of ICP transducers.

Intracranial pressure (ICP) monitoring has become the mainstay of multimodal neuromonitoring of comatous patients after head injury. In the presence of rising ICP and faced with pressures, difficult to control, aggressive measures, such as hypothermia may be used. The ICP readings should not be influenced by temperature changes. A laboratory test was designed to simulate temperature variations between 20 degrees C and 45 degrees C at different pressure levels under physiological conditions. Five types of transducers were examined: Epidyn Braun Melsungen, ICT/B-Titan Gaeltec, Camino-OLM-110-4B, Codman MicroSensor ICP-Transducer, Neurovent ICP transducer Rehau Ag+Co. Tests were performed at 6 different pressure levels between 0 mmHg and 50 mmHg. The results show very low drifts of less than 0.15 mmHg degree C-1 for Codman, Epidyn and Neurovent. Gaeltec and Camino exhibited higher drifts of 0.18 mmHg and 0.2 mmHg degree C-1 respectively. Within the temperature range from 35 degrees C to 42 degrees C all probes tested show insignificant temperature drift. Whether these results also apply to other types of transducers needs further evaluation. Problems and requirements related to the design of a laboratory test for the in vitro assessment of ICP transducers are discussed in detail.

Jumping translocation of 1q as the sole aberration in a case of follicular lymphoma.

Cytogenetic and fluorescence in situ hybridization (FISH) studies in a case of follicular lymphoma grade III showed a "jumping translocation" of chromosome 1q21-qter to chromosomes Xq28 and 18q23, which resulted in a partial trisomy 1q as the only chromosome aberration. This case represents, to the best of our knowledge, the first report of a jumping translocation in a malignant lymphoma occurring as the sole aberration.

Trisomy 3 is not a common feature in malignant lymphomas of mucosa-associated lymphoid tissue type.

The genetic background of extranodal marginal zone B-cell non-Hodgkin's lymphoma (NHL) of mucosa-associated lymphoid tissue (MALT) type is poorly understood. In contrast to most entities of primary nodal lymphomas, few cytogenetic data are available, and gene rearrangements frequently encountered in and highly characteristic of certain entities of systemic NHL are absent in this type of lymphoma. Recently, it was suggested that MALT-type NHLs are associated with certain numerical chromosome aberrations and especially with trisomy 3. We performed an extensive study using a sensitive double (bicolor) fluorescence in situ hybridization technique for the analysis of trisomies for chromosomes 3, 7, 12, and 18 in 60 samples of low-grade and 45 high-grade MALT-type tumors. In the low-grade cases, trisomy 3 was found in a frequency of only 20%. High-grade lymphomas of MALT type were associated with trisomies 3, 7, 12, and 18 in 36, 20, 18, and 13% of the cases, respectively. Whereas no difference was encountered for trisomy 3 in primary and secondary/simultaneous high-grade lymphomas, +7 and +12 were associated with primary lymphomas, and a +18 was predominantly found in secondary/simultaneous high-grade NHL. These results challenge earlier reports describing a high frequency of +3 in low-grade MALT-type NHL and indicate a possibly different genetic evolution pattern of primary and secondary/simultaneous high-grade lymphomas of primary mucosal origin.

Chromosomal abnormalities in nodal and extranodal CD30+ anaplastic large cell lymphomas: infrequent detection of the t(2;5) in extranodal lymphomas.

To determine the significance of the t(2;5)(p23;q35) translocation in nodal and extranodal anaplastic large cell lymphoma (ALCL), we performed cytogenetic, molecular genetic, and immunohistochemical analyses of tumor tissues from 11 patients with CD30+ ALCL. Three of five patients with nodal ALCL had additional infiltration of the skin. Six patients had extranodal ALCL, two had primary intestinal ALCL, three had a primary cutaneous ALCL, and one had osseous ALCL. Cytogenetic investigation detected the t(2;5) in all patients with nodal ALCL but not extranodal ALCL. Tumor cells in t(2;5)+ lesions also stained immunohistochemically for p80NPM/ALK, whereas no staining for p80NPM/ALK was detected in extranodal ALCL. Two extranodal lesions had NPM/ALK fusion transcripts detected by nested reverse transcriptase-polymerase chain reaction. Fluorescence in situ hybridization analysis of these two lymphomas showed in one case a significant number (4%) of cells with a split hybridization signal, indicative of disruption of the NPM gene. Additional recurrent breakpoints observed in extranodal ALCL were 1p36, 6p25, and 8q24. Loss of genetic material occurred at 6q in one extranodal ALCL. Our results suggest that the t(2;5) more frequently plays a pathogenetic role in primary nodal than in extranodal ALCL and that this translocation may not be the primary event in some CD30+ ALCL.

Abdominal T-cell non-Hodgkin's lymphoma of the gamma/delta type in a patient with selective immunoglobulin A deficiency.

A 28-year-old man presented with selective immunoglobulin A deficiency and severe diarrhea responding to a gliadin-free diet. Biopsy samples of the small intestine showed dense T-cell infiltrations in the lamina propria and a slight increase of intraepithelial T-lymphocytes. No clonal rearrangement of the T-cell receptor c-beta chain genes was detectable by Southern blotting. Four years later, at the age of 32, the patient was hospitalized again with liver failure, abdominal lymphadenopathy, pancytopenia, and recurrent bacterial infections. Retrospective polymerase chain reaction analysis of formalin-fixed tissues of the intestinal biopsy samples obtained 4 years earlier showed monoclonal T-cell receptor gamma-chain gene rearrangement. Lymphoid cells of the peripheral blood showed an immunophenotype of CD3-positive gamma/delta T cells with a negativity for CD4 and CD8. A clonally rearranged T-cell receptor delta chain gene and a germline configuration of the c-beta chain genes was found by Southern blotting. Cytogenetics showed an abnormal karyotype with unbalanced translocations t(1;5) and t(9;13). The patient died of extensive lung infiltrations by gamma/delta T cells; autopsy showed a peripheral T-cell lymphoma of the gamma/delta type in the enlarged abdominal lymph nodes. This is the first report of an abdominal T-cell lymphoma of the gamma/delta type in a patient with selective immunoglobulin A deficiency.