Clonal changes in inflammatory pseudotumor of the lung. A case report

Abstract

Background. Pulmonary inflammatory pseudotumor, also known as plasma cell granuloma among many other names, is widely believed to be an inflammatory or reactive lesion rather than a neoplasm, although its pathogenesis is still controversial. Methods. Cytogenetic analysis was performed on a lung mass that showed typical clinical and pathologic features of inflammatory pseudotumor. Ultrastructural and immunohistochemical studies were performed in addition to routine histologic examination. Results. Cytogenetic study of the lesion revealed clonal anomalies of t(1;2)(q21;p23) and del(4)(q27). The patient, a 30‐year‐old woman, presented with an asymptomatic but enlarging right lower lobe mass for which partial right lower lobectomy was performed. The lung mass was well circumscribed radiographically and grossly. Microscopically, it was characterized by a loosely arranged spindle cell proliferation with prominent plasma cell infiltration. Fibroblastic and myofibroblastic differentiation of the spindle cells was demonstrated by ultrastructural and immunohistochemical studies. Conclusion. To the authors' knowledge, this is the first report of clonal cytogenetic changes in a clinically and pathologically typical case of inflammatory pseudotumor in the lung. This finding suggests that pulmonary inflammatory pseudotumor might be a true neoplasm rather than a purely inflammatory or reactive lesion. Cancer 1995; 76:1545‐9.

TPM3-ALK and TPM4-ALK Oncogenes in Inflammatory Myofibroblastic Tumors

“…The cytogenetic features of cases 1, 2, 6, and 11 have been described previously. 6,8,9 Cytogenetic banding analyses had not been performed in the remaining seven cases.…”

“…[5][6][7][8][9][10] Approximately 50% of soft-tissue IMT karyotypes contain clonal rearrangements of the chromosome 2 short arm, [5][6][7][8][9][10] and each of two cytogenetically characterized IMTs arising in bone contained rearrangements of the HMGIC region on chromosome band 12q15. 8 Recently, Griffin et al 10 showed that IMT 2p rearrangements fall within an ϳ100-kb region containing the ALK receptor tyrosinekinase locus, on chromosome band 2p23.…”

Primary inflammatory myofibroblastic tumor of the breast with rapid recurrence and metastasis: A case report

“…Some consider IMT to be an immunological response to an infectious or noninfectious insult (31,32). Other researchers found that there was ectopic chromosomal rearrangements in the long arm of chromosome 2 and the short arm of chromosome 9, and confirmed that IMT was a monoclonal proliferation by genetic and molecular techniques (33)(34)(35)(36). In addition, approximately half of IMTs harbor a clonal cytogenetic aberration that activates the ALK-receptor tyrosine kinase gene at 2p23 (15,37).…”

Exophytic inflammatory myofibroblastic tumor of the stomach in an adult woman: A rare cause of hemoperitoneum

“…It has been debated whether IMT is a tumor or inflammation, and also whether it is benign or malignant [1] . However, recent studies on cytogenetic abnormalities, such as rearrangements of the ALK gene on chromosome 2p23 [4,5] , clonal chromosome abnormalities [6][7][8] , and DNA aneuploidy [9] , and the role of oncogenic viruses [10,11] in the pathogenesis of IMT suggest that it is a true neoplasm. According to the current classification of the World Health Organization [12] , IMT is a neoplasm with a tendency for local recurrence and a very low rate of metastasis, and is histopathologically composed of myofi broblastic spindle cells, with inflammatory cell infiltrate of plasma cells, lymphocytes and eosinophils.…”