ABSTRACT
A 7-year-old boy with no history of malnutrition or diarrhoea complained of acute abdominal pain, was diagnosed with acute appendicitis, and underwent appendectomy. Histologically, a diffuse infiltrate of large atypical lymphoid cells was found in the entire appendiceal wall. Immunohistochemical examination revealed that the tumour cells expressed T-cell receptor (TCR)-ßF1, CD3, CD4, CD25, cytotoxic-related protein TIA1 and granzyme-B, but were negative for CD8, Foxp3, CD20, CD30 and CD56. Polymerase chain reaction (PCR) revealed clonal bands of TCR-γ gene products in the tumour tissue. No anti-cytomegalovirus antibody-positive cells were detected. In situ hybridization revealed no nuclear signals of Epstein-Barr virus (EBV)-encoded RNA. Helicobacter pylori infection was detected in tumour tissue by anti-East Asian cytotoxin-associated gene (Cag) A antibody and PCR using its specific primers. The patient received chemotherapy and has remained in remission for 2 years. To the best of our knowledge, only two cases of appendiceal T-cell non-Hodgkin lymphoma (NHL) have been reported, both in elderly patients. We believe that this is the first reported case of childhood CD4- and TIA1-positive cytotoxic T (Th1)-cell NHL in the appendix or gastrointestinal tract. Helicobacter pylori infection might be an initiator of atypical cytotoxic T-cell proliferation. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1302380563830412.
Subject(s)
Appendiceal Neoplasms/pathology , Lymphoma, T-Cell/pathology , Abdominal Pain/etiology , Appendectomy , Appendiceal Neoplasms/chemistry , Appendiceal Neoplasms/complications , Appendiceal Neoplasms/genetics , Appendiceal Neoplasms/microbiology , Appendiceal Neoplasms/surgery , Appendicitis/etiology , Biomarkers, Tumor/analysis , Biomarkers, Tumor/genetics , Chemotherapy, Adjuvant , Child , Genes, T-Cell Receptor gamma , Helicobacter pylori/isolation & purification , Humans , Immunohistochemistry , Lymphoma, T-Cell/chemistry , Lymphoma, T-Cell/complications , Lymphoma, T-Cell/genetics , Lymphoma, T-Cell/microbiology , Lymphoma, T-Cell/surgery , Male , Polymerase Chain Reaction , Time Factors , Treatment OutcomeABSTRACT
Mycobacterial pseudotumor (MP) is a rare pathologic presentation of both Mycobacterium tuberculosis and non-tuberculous mycobacterial disease, hitherto reported to occur only in immunosuppressed patients with or without human immunodeficiency virus infection. This lesion shares close pathologic resemblance to certain mesenchymal neoplasms, particularly Kaposi's sarcoma (KS), from which it must be properly differentiated due to distinct prognosis and therapy. We report a case of MP obliterating the lumen of the appendix vermiformis in a 34-years-old patient who died of complications of AIDS at our hospital in Rio de Janeiro. A total of 24 cases of MP (including our patient) have been described in the literature. MP has been found especially in lymph nodes, but extranodal lesions have been described in the skin, spleen, lung, bone marrow, brain and, in our patient, the appendix vermiformis. We offer a review of the other 23 published case reports of MP in both HIV-infected and uninfected patients and discuss the pathologic features that differentiate MP from KS.
