Typical Lung Carcinoids with Metastasis: Potential Role of MicroRNAs in the Regulation of Adaptive Immunity Associated with Disease: a Case Study.

BACKGROUND/AIMS: Lung carcinoids are uncommon neuroendocrine tumours. Molecular features of lung carcinoids have been poorly defined. microRNAs (miRNAs) are potent gene expression regulators with important roles in cancer development and progression. However, little is known on the role of miRNAs in the pathogenesis of lung carcinoids. Our goals were to identify commonly deregulated miRNAs in a rare case of lung carcinoid of typical histology with metastasis, as well as map miRNA target genes in pathways potentially associated with disease development and progression. METHODS: miRNA expression profiles were assessed using the TaqMan Low Density Arrays, which is a platform including 384 miRNAs. miRNA profiles were generated in the tumor and its corresponding lymph node metastasis, compared to reference normal lung tissues. Furthermore, miRNA expression was validated in a separate, publicly available external dataset (n=19 typical lung carcinoids; 2/19 were metastatic tumors, compared to six normal lung tissues, GSE77380). Following this analysis, computational tools were applied for data interpretation. miRTarBase was used to determine miRNA-target genes, followed by ToppGene Suite analysis to identify pathways and biological functions. In addition, the expression of genes targeted by miRNAs was validated in a second, separate external dataset (n=13 tumour samples, GSE35679). GEO2R data analysis tool was used in both validation analyses (miRNAs and genes). RESULTS: We identified 15 commonly significantly downregulated miRNAs (fold change, FC≥2 and p<0.05) in the tumour and its paired metastasis, with further decreasing levels in the metastatic lesion. Downregulation of miR-126-3p and miR-146b-5p was validated in the external dataset GSE77380. In addition, SOX2 and TCF4 genes, targeted by miR-126-3p, were consistently overexpressed in a subset of six typical lung carcinoids from the external dataset GSE35679. Pathways analysis showed that miRNAs miR-126-3p and miR-146b-5p target genes with a role in the regulation of adaptive immune response. CONCLUSION: Our results contribute to the identification of miRNA expression changes in a typical lung carcinoid and its corresponding lymph node metastasis. Down-regulated levels of miR-126-3p and miR-146b-5p and target gene over-expression could play a role in the progression of this case of primary typical lung carcinoid to regional metastasis. Identified miRNAs and target genes are potential candidates for validation in a larger number of cases.

The immune microenvironment in typical carcinoid lung tumour, a brief report of four cases.

Pulmonary typical carcinoid (TC) is a low-grade, rare lung cancer of neuroendocrine origin. Currently, there is very little information available about the immune cell composition in TC tumours. Here, we analysed by flow cytometry resected tumours from four never-smoker female patients with TC. Twelve distinct immune cell types were identified in TC tumours. The most abundant immune cells were CD8+ T cells, CD4+ T cells, B cells and macrophages, which represented 19.8%, 17.7%, 11.5% and 11% of all tumour-infiltrating CD45+ leucocytes, respectively. Natural killer (NK) cells (8.8%) and neutrophils (3.9%) were also common. Three types of dendritic cells (DCs) were identified (plasmacytoid DCs, CD1c  DCs, and CD141  DCs) which together constituted 1.4% of all immune cells in TC tumours. Small populations of basophils (1.2%), mast cells (0.8%) and eosinophils (0.6%) were also present. Notably, the percentage of leucocytes (of all living cells) was much lower in TC tumours compared to high-grade non-small cell lung cancer (NSCLC) tumours and also compared to non-cancerous lung tissue. We conclude that TC tumours are relatively non-inflammatory, although the immune landscape was found to be very complex.

Appendix Tumor Microenvironment.

The pathological features of the appendix tumors fundamentally recall those of the more frequent colorectal neoplasms, although with a higher relative incidence of carcinoids, due to the abundant presence of enteroendocrine cells in the appendix wall. Moreover, different types of lymphomas, Hodgkin and non-Hodgkin, arising from the extra-nodal mucosal-associated lymphatic tissue, can be encountered. The appendix tumor microenvironment (TME) consists of a cellular component and of a noncellular component: the former includes the immunocompetent cells, while the latter represents the support stroma. Particularly in carcinoids, the immune cell reaction can be explicated by tumor-infiltrating lymphocytes, which, in some circumstances, may arrange around and inside the tumor in a brisk fashion influencing favorably the prognosis. This active reaction has to be distinguished from any preexisting inflammatory condition of the appendix and from superimposed tumor complications, such as infection or ischemia. In practice, we consider the appendix TME a complex framework with immunological, mechanic, and metabolic functions, all supported by a marked neo-lymphoangiogenesis.

Circulating cytokines and monocyte subpopulations as biomarkers of outcome and biological activity in sunitinib-treated patients with advanced neuroendocrine tumours.

BACKGROUND: Sunitinib is approved worldwide for treatment of advanced pancreatic neuroendocrine tumours (pNET), but no validated markers exist to predict response. This analysis explored biomarkers associated with sunitinib activity and clinical benefit in patients with pNET and carcinoid tumours in a phase II study. METHODS: Plasma was assessed for vascular endothelial growth factor (VEGF)-A, soluble VEGF receptor (sVEGFR)-2, sVEGFR-3, interleukin (IL)-8 (n=105), and stromal cell-derived factor (SDF)-1α (n=28). Pre-treatment levels were compared between tumour types and correlated with response, progression-free (PFS), and overall survival (OS). Changes in circulating myelomonocytic and endothelial cells were also analysed. RESULTS: Stromal cell-derived factor-1α and sVEGFR-2 levels were higher in pNET than in carcinoid (P=0.003 and 0.041, respectively). High (above-median) baseline SDF-1α was associated with worse PFS, OS, and response in pNET, and high sVEGFR-2 with longer OS (P⩽0.05). For carcinoid, high IL-8, sVEGFR-3, and SDF-1α were associated with shorter PFS and OS, and high IL-8 and SDF-1α with worse response (P⩽0.05). Among circulating cell types, monocytes showed the largest on-treatment decrease, particularly CD14+ monocytes co-expressing VEGFR-1 or CXCR4. CONCLUSIONS: Interleukin-8, sVEGFR-3, and SDF-1α were identified as predictors of sunitinib clinical outcome. Putative pro-tumorigenic CXCR4+ and VEGFR-1+ monocytes represent novel candidate markers and biologically relevant targets explaining the activity of sunitinib.

Updated features associated with type 1 gastric carcinoids patients: a single-center study.

OBJECTIVE: Data on clinical presentation and associated features of patients with type 1 gastric carcinoids (T1-GCs) are scanty. This study aimed to provide detailed data on a series of patients with T1-GCs. MATERIAL AND METHODS: Clinical, laboratory, endoscopic, and histological data were assessed from 31 T1-GCs patients (cross-sectional design), consecutively diagnosed in a tertiary center according to a standardized diagnostic protocol. T1-GCs were diagnosed at baseline or follow-up gastroscopy for atrophic gastritis in 74.2% and 25.8% of patients, respectively. RESULTS: Seventy-one percent of T1-GC patients were female. Age ranged from 23 to 78 (median 58 years). T1-GCs were more frequently diagnosed between 40-49 years (35.5%) and 60-69 years (32.3%) (p = 0.0383). Thyroid disease was present in 54.8% (in 29% autoimmune). All 31 patients had either cobalamin or iron deficiency with or without anemia. Manifest pernicious anemia was present in 67.7% of patients and cobalamin deficiency without anemia in 9.7% patients. Iron deficiency anemia was present in 29% and iron deficiency without anemia in 12.9% of patients. In 48.4% of patients, T1-GCs appeared as polyps, which were single in all cases and had a median size of 4 mm (range 2-15 mm). In patients with polypoid T1-GCs, thyroid disease of autoimmune and nonautoimmune origin (p = 0.0181) was more frequently associated. CONCLUSION: This study shows that T1-GCs may be diagnosed at any age. Autoimmune features are frequently present as well as cobalamin and iron deficiency. The copresence of autoimmune diseases and micronutrient deficiencies should be accurately investigated, in particular in patients with polypoid T1-GCs.

Gastric type I carcinoid: a pilot study with human G17DT immunogen vaccination.

CONTEXT: Gastric type I carcinoid is a rare neoplasm, deriving from enterochromaffin-like cells (ECL), mainly affecting women with autoimmune gastritis. The approach to treatment, either endoscopic, medical or surgical, is not well defined, particularly in multifocal tumours or carcinoids with rapid growth/frequent recurrence. OBJECTIVE: To determine whether an anti-G17 vaccination might interfere on the natural history of gastric type I carcinoid. SETTING: Padua teaching Hospital, outpatient clinic. DESIGN AND PATIENTS: Three patients with type I gastric carcinoid in autoimmune gastritis were administered, after informed consent and ethic committee approval, with a vaccine against gastrin 17 (G17), a synthetic peptide that stimulates specific and high-affinity anti-G17 antibodies, and followed up endoscopically and clinically for a mean of 36 months. MAIN OUTCOME MEASURES: Gastric histology and specifically carcinoid growth/recurrence and trend in time in gastrin, G17, pepsinogens, chromogranin A and clinical parameters. RESULTS: Following vaccination, carcinoid regression was observed in 2/3 patients and, in one of the patients, even the disappearance of ECL hyperplasia, with a reduced ECL cells stimulation, confirmed by a significant reduction in chromogranin A levels. Regression was observed in the two patients that showed a more clear local response to the vaccine. Increased autoantibody titre was observed, but no appearance of new autoimmune diseases. CONCLUSIONS: Anti-G17 vaccination induced regression of type I gastric carcinoid and could be considered for the treatment of this tumour, when endoscopic removal is not indicated.

Expression of L-type amino acid transporter 1 (LAT1) in neuroendocrine tumors of the lung.

Amino acid transport systems play an important role in cellular proliferation. L-type amino acid transporter 1 (LAT1) has been associated with tumor growth, and is highly expressed in the established tumor cell lines and primary human neoplasms. In this study, we investigated the expression of LAT1 to evaluate the malignant potential and prognostic significance in neuroendocrine (NE) tumors of the lung. Twenty-one surgically resected, large cell neuroendocrine carcinomas (LCNEC), 13 small cell lung cancers (SCLC), five atypical carcinoids (AC), and 10 typical carcinoids (TC) were enrolled in the study. LAT1 expression and Ki-67 labeling index of the NE tumors were analyzed by immunohistochemical staining. LAT1 was overexpressed in 52.4% of the LCNEC, in 46.2% of the SCLC, and in 25% of the AC. LAT1 expression in LCNEC was significantly associated with lymph node metastasis and poor outcome. Moreover, a significant correlation was found between LAT1 expression and Ki-67 in both LCNEC and SCLC. Expression of LAT1 tended to increase from low-grade to high-grade NE tumors. The present results suggest that LAT1 may play a significant role in cellular proliferation, lymph node metastasis, and poor outcome in patients with NE tumors of the lung.

Gastrointestinal carcinoid tumor and chylous ascites, a rare association with a poor prognosis. A case report.

Gastrointestinal carcinoid is a rare tumor. The association of this tumor with chylous ascites is uncommon. A review of the English-language literature carried out in 2002 identified only 15 cases. We report a case of chylous ascites, gastrointestinal carcinoid tumor and elevated blood levels of CA-125 in a patient who did not respond to chemotherapy.

[Goblet-cell carcinoid of the colon].

The authors describe a case of goblet-cell carcinoid of the appendix subject to additional immunohistological study. Goblet-cell carcinoid is a rare colonic tumor comprises the morphological signs of adenocarcinoma and carcinoid.

A distinct role for interleukin-13 in Th2-cell-mediated immune responses.

Immune responses elicited by allergic reactions and parasitic worm infections are characterised by the induction of T helper 2 (Th2) cells. These cells secrete cytokines such as interleukin-4 (IL-4), IL-5 and IL-13, which induce the production of immunoglobulin E (IgE) and eosinophils [1,2]. Previous studies using gastrointestinal nematodes to elucidate the role of Th2-cell-mediated immune responses have demonstrated a causal relationship between T cells and worm expulsion (reviewed in [3]). Although it has been proposed that IL-4 played a central role in these responses, recent studies demonstrated that IL-4-/- mice expel the parasitic gastrointestinal nematode Nippostrongylus brasiliensis normally [4], suggesting that another T-cell mediator is required for efficient worm clearance. Using IL-13-/- mice, we have demonstrated that, unlike wild-type and IL-4-/- mice, the IL-13-/- animals failed to clear N. brasiliensis infections efficiently, despite developing a robust Th2-like cytokine response to infection. Furthermore, treatment of the IL-13-/- mice with exogenous IL-13 resulted in a reduction in the numbers of worms recovered. The IL-13-/- animals also failed to generate the goblet cell hyperplasia that normally occurs coincident with worm expulsion. This observation may link IL-13 with the production of intestinal mucus which is believed to facilitate worm expulsion. These data support a unique role for IL-13 in Th2-cell-mediated immune responses and demonstrate that IL-13 and IL-4 are not redundant.

Treatment of malignant carcinoid tumors with recombinant interferon alfa-2b: development of neutralizing interferon antibodies and possible loss of antitumor activity.

Twenty patients with malignant carcinoid tumors were treated for 6 months with recombinant interferon alfa-2b (IFN alpha-2b; Intron-A; Schering Corp., Bloomfield, NJ) at a mean dose of 5.9 megaunits three times per week. Eleven of the 20 patients (55%) had a greater than 50% reduction of tumor markers (urinary 5-hydroxyindoleacetic acid or plasma neuropeptide K), showing objective tumor response. Six patients (30%) had stable disease with no significant change in tumor markers or tumor size, and three (15%) had progressive disease with an increase in tumor markers and size. These results are similar to those reported earlier for treatment with natural leukocyte IFN in patients with carcinoid tumors. Only two patients (35%) had a slight reduction of tumor size after 6 months of treatment. Three patients developed neutralizing antibodies to IFN alpha-2b. Two of these patients initially showed an objective response, which lasted until IFN antibodies developed. In one of these patients, a change to human leukocyte IFN resulted in normalization of antibody titers within 3 months, and the patient had a second objective clinical response. There was no correlation between development of IFN antibodies and development of autoimmune phenomena such as increased titers of antinuclear antibodies or thyroid autoantibodies. IFN alpha-2b seems to be as potent as human leukocyte IFN in the treatment of patients with malignant carcinoid tumors, but it is important to recognize that antibodies neutralizing IFN may develop in some patients, with concomitant loss of antitumor effects. A change to natural leukocyte IFN might be beneficial in these patients.

Preferential expression of immunoreactive fucosylceramide in adenocarcinoma of the lung.

The expression of fucosylceramide (PC47H antigen) in 97 lung cancers and 4 extrapulmonary squamous cell carcinomas was examined with the use of a novel monoclonal antibody, PC47H, recognizing fucosylceramide specifically. The observed variation in fucosylceramide content was dependent on the degree of glandular differentiation in adenocarcinoma of the lung. Fucosylceramide was abundantly expressed in well differentiated adenocarcinoma of the lung and poorly expressed in poorly differentiated adenocarcinoma. Some squamous cell carcinomas of the lung reacted with this monoclonal antibody weakly, but the reaction was noted only at the periphery of the epithelial sheets. Extrapulmonary squamous cell carcinoma and small-cell carcinomas did not react with monoclonal antibody PC47H. Interestingly, large cell carcinomas of uncertain cell origin were all positive for fucosylceramide, which accumulated in the cytoplasm. At the ultrastructural level, fucosylceramide was located in the plasma membrane and unit membrane of the rough endoplasmic reticulum. On the other hand, carcinoembryonic antigen as an adenocarcinoma-associated tumor marker was expressed significantly in squamous cell carcinomas as well as adenocarcinomas. Taken together, fucosylceramide seems to be expressed preferentially in adenocarcinomas, and is closely linked to glandular differentiation. Thus it may be a better tumor marker than carcinoembryonic antigen.

Antibodies against gastrointestinal carcinoid tumors in IDDM.

In this study, 92% of patients' serums known to contain antibodies against islet cells, including the Juvenile Diabetes Foundation provisional reference serum, had antibodies reacting with gastrointestinal carcinoid tumors. Twelve percent of the control serums from healthy individuals bound to carcinoid cells, and 2% bound to islet cells. Seventy-five percent of the children with newly diagnosed insulin-dependent diabetes mellitus had carcinoid tumor antibodies, and 83% had islet cell antibodies. These findings suggest that antigenic determinants are shared between endocrine cells of islets of Langerhans and neuroendocrine tumors of the same embryological derivation. Carcinoid tumors may not only provide an alternative source for islet cell antibody assays but also supply material for isolation of antigens possibly involved in the immunopathogenesis of diabetes.

The distribution of CD34-positive stromal cells and myofibroblasts in colorectal carcinoid tumors.

In order to understand the stromal reaction associated with colorectal neoplasms, we examined specimens from 26 patients including normal colorectal tissues (n=15), carcinoid tumors (n=12), well differentiated adenocarcinomas (n=10), and poorly differentiated adenocarcinomas (n=4), using an immunohistochemical method. Myofibroblasts and CD34-positive stromal cells were distributed in the mucosa and in the area between the submucosal and subserosal layers, respectively. However, the distribution of these cells markedly changed with the invasion of neoplasms. Namely, myofibroblasts were abundant in the invasive stroma of all colorectal neoplasms. CD34-positive stromal cells were completely absent from the invasive stroma of colorectal cancers. On the other hand, CD34-positive stromal cells were absent from four out of five carcinoid tumor cases with lesions measuring less than 2 mm in size, but were present in all seven cases of carcinoid tumors measuring more than 2 mm. Double-immunostaining identified stromal cells expressing both ASMA and CD34 in several carcinoid tumor cases. Finally, no CD34-positive stromal cells were observed in the invasive stroma of colorectal cancers. However, the distribution of these cells in carcinoid tumors may depend on the lesion size. Namely, CD34-positive stromal cells existed between neoplastic nests in large-sized carcinoid tumors. Myofibroblasts in the stroma of colorectal neoplasms may originate from CD34-positive stromal cells.

Primary carcinoid tumor of the common hepatic duct: A rare case with immunohistochemical and molecular findings.

We report immunohistochemical (IHC) and molecular findings in a rare case of a carcinoid tumor of the extrahepatic bile ducts in a 33-year-old woman, who presented with a 3.9x2.8x2.6 cm mass within the right and common hepatic ducts. She underwent surgery and a carcinoid tumor was identified. This lesion is of interest because in addition to the morphological and cytological features of a typical carcinoid, it demonstrated a distinct pleomorphic area immunoreactive for gastrin. By molecular analysis, loss of heterozygosity (LOH) with opposite allelic patterns between the gastrin-positive and gastrin-negative areas of the tumor was identified. The molecular studies for LOH along with the morphology and IHC profiling suggest that this second population of gastrin-positive carcinoid cells may represent a new clone within the carcinoid tumor with differentiation toward gastrin production or may represent the next step in the carcinogenic process with a gradual emergence of a more aggressive clone.

Differential expression and prognostic value of the chemokine receptor CXCR4 in bronchopulmonary neuroendocrine neoplasms.

INTRODUCTION: For many tumors, the overexpression of the chemokine receptor CXCR4 is associated with increased malignancy and poor patient outcomes. However, comprehensive data for neuroendocrine neoplasms of the lung are still lacking. METHODS: CXCR4 expression was evaluated in a panel of bronchopulmonary neuroendocrine neoplasms (BP-NEN) comprising typical carcinoids (n = 26), atypical carcinoids (n = 30), and small cell lung cancers (SCLC, n = 34). Samples were analyzed by immunohistochemistry using the novel monoclonal rabbit anti-human CXCR4 antibody UMB-2 and by qRT-PCR. The expression was correlated with clinical data and overall patient survival. RESULTS: CXCR4 was predominantly localized at the plasma membrane of the tumor cells. CXCR4 was expressed with a high intensity in almost all of the 30 SCLC samples. In contrast, it was detected infrequently and with low intensity in the typical carcinoid and atypical carcinoid samples. There was a significant correlation between the immunohistochemistry and qRT-PCR data. Additionally, there was a significant negative relationship between CXCR4 expression and overall survival. CONCLUSIONS: With increasing malignancy, BP-NEN clearly differ in the extent of CXCR4 expression. As in other tumor entities, CXCR4 overexpression significantly correlates with negative patient outcome. Due to its particular high expression rate in SCLC, CXCR4 may serve as a promising new target for diagnostic and pharmacological intervention as well as for peptide receptor-based radionuclide therapy.

Autoantibodies in thymoma-associated myasthenia gravis with myositis or neuromyotonia.

BACKGROUND: About 50% of patients with thymoma have paraneoplastic myasthenia gravis (MG). Myositis and myocarditis or neuromyotonia (NMT) will also develop in some. Patients with thymoma-associated MG produce autoantibodies to a variety of neuromuscular antigens, particularly acetylcholine receptor (AChR), titin, skeletal muscle calcium release channel (ryanodine receptor [RyR]), and voltage-gated potassium channels (VGKC). OBJECTIVE: To examine whether neuromuscular autoantibodies in patients with thymoma correlate with specific clinical syndromes. METHODS: Serum and plasma samples from 19 patients with thymoma-associated MG, of whom 5 had myositis and 6 had NMT, underwent testing for antibodies to AChR, titin, RyR, and VGKC. RESULTS: Antibodies to AChR and titin were found in 19 and 17 patients, respectively. Antibodies to RyR correlated with the presence of myositis (P = .03); they were found in all 5 patients with myositis and in only 1 patient with NMT, but also in 4 of 8 patients with neither disease. Antibodies to VGKC were found in 4 patients with NMT, 1 of 3 patients undergoing testing for myositis, and 2 of 7 patients undergoing testing with neither comorbidity. Presence of RyR antibodies correlated with high levels of titin antibodies. CONCLUSIONS: The results appear to distinguish partially between 3 groups of patients with thymoma-associated MG: the first with RyR antibodies and myositis or myocarditis, the second with NMT without RyR antibodies, and the third without RyR antibodies, myositis, or NMT. Differences in the thymoma may underlie these pathologic associations.

Primary prostatic carcinoid tumor with intracytoplasmic prostatic acid phosphatase and prostate-specific antigen.

A case of prostatic carcinoid tumor with lymph node metastases is reported. The patient was a 78-year-old male who died in ventricular fibrillation. At autopsy, a 2 X 2 cm, white, irregular tumor was found in the prostate and there were several enlarged para-aortic lymph nodes. Both specimens contained a characteristic carcinoid tumor. Argyrophil stains revealed strong positivity in the primary as well as in the metastatic tumors. Electron micrographs prepared from formalin-fixed tissue demonstrated numerous membrane-bound dense-core granules. Immunoperoxidase-labeled antibodies against both prostatic acid phosphatase and prostate-specific antigen localized in the tumor cells. The ultrastructural and immunohistochemical results support differentiation of the tumor cells toward both prostatic epithelial cells and endocrine cells. We believe that this is the first reported case of a prostatic carcinoid tumor in which specific prostatic tissue markers have been demonstrated in the tumor cells.

Transmembrane protein tyrosine phosphatase IA-2 (ICA512) is expressed in human midgut carcinoids but is not detectable in normal enterochromaffin cells.

A potential upregulation of receptor type protein tyrosine phosphatase IA-2 (ICA512) expression was detected by differential display and investigated in midgut carcinoid tumours. Normal intestine tissue and tumour tissue from 13 midgut carcinoid patients were studied by in situ hybridisation using an IA-2 ribonucleotide probe and confocal microscopy using specific IA-2 antibodies. Previously, it had been shown that IA-2 is located in the secretory granules of virtually all neuroendocrine cells. However, we found that IA-2 was not detectable in resting normal enterochromaffin (EC) cells of the small intestine, while high expression of IA-2 mRNA and protein was confirmed in both primary and metastatic carcinoid tissue. This difference in expression was not observed with chromogranin A or serotonin, two secretory granule hormones known to be expressed in EC cells, indicating that IA-2 was seemingly not necessary for the basal production and packaging of these hormones. When comparing patients receiving biotherapy before operation with untreated patients, we found expression of IA-2 to be lower in tumours from patients that had been treated with a combination of alpha-interferon and the somatostatin analogue, octreotide. There was no correlation between IA-2 expression and proliferation rates as measured by immunohistochemistry with antibodies against the Ki 67 antigen. Furthermore, we show that IA-2 is co-localised with serotonin in carcinoid tumours as well as in the pancreatic tumour cell line, BON1, which is interesting as serotonin secretion rate is presumably higher in tumour cells than in resting EC cells. Taken together, these findings may indicate a role for IA-2 in the later stages of the regulated secretory process.

Synchronous occurrence of carcinoid tumour of the appendix and T-cell lymphoma of the ileum. A case report with review of the literature.

Carcinoid tumours of the gastrointestinal tract are often associated with other tumour types at various sites. However, only rarely has a lymphoma constituted the second tumour. In the present paper, we report the case of a 62-year-old woman who was operated on for a perforated T-cell lymphoma of the ileum and in whom an appendicular carcinoid tumour was incidentally discovered at surgery. It was possible to completely remove both tumours and postoperatively the patient underwent CHOP treatment. Ten months after surgery the patient is well, with no tumour manifestations. We also discuss problems concerning classification of the lymphoma on account of loss of the T-cell antigen CD45RO (UCHL-1).