Consistency of Isochromosome 7q and Trisomy 8 in Hepatosplenic γδ T-cell Lymphoma: Detection by Fluorescence in Situ Hybridization of a Splenic Touch-Preparation from a Pediatric Patient

Abstract

Hepatosplenic gamma-delta (gammadelta) T-cell lymphoma is a rare but increasingly recognized lymphoid malignancy predominantly affecting young adult males. It is not well appreciated in the pediatric population. We report the third case of this aggressive lymphoma in a child as well as additional support for the consistency of the recently discovered cytogenetic abnormalities, isochromosome 7q and trisomy 8, which in this case were documented using fluorescence in situ hybridization (FISH) of a touch-preparation of the spleen.

Hepatosplenic T-cell lymphoma is a rare clinicopathologic entity with poor outcome: report on a series of 21 patients

“…Therefore, in the context of antigen-driven stimulation of reactive ␥␦ T cells, it is tempting to speculate that neoplastic transformation could result from a multistep process involving impairment of the immune system (as in the patients receiving immunosuppressive therapy) or additional genetic alterations such as isochromosome arm 7q. The latter aberration was present in 9 of 13 documented cases, further confirming the association between HS␥␦TCL and isochromosome arm 7q, which was reported as a hallmark not only of HS␥␦TCL 12,14,25,[28][29][30][31][32] but also of its unusual ␣␤ immunophenotypic variant. 33,35 Although the mechanism by which it might contribute to the pathogenesis of HSTCL is unknown, its previously reported accumulation in forms with features of cytologic progression suggests that it benefits the outgrowth of malignant clones.…”

“…The identification of this lymphoma subtype, recognized as a provisional entity in the Revised European American Lymphoma (REAL) classification, 26 has been further supported by its cytotoxic phenotype 11,27 and its strong association with the isochromosome arm 7q cytogenetic abnormality. 12,14,25,[28][29][30][31][32] More recently, a few cases of HSTCL with sinusoidal infiltration and an ␣␤ T-cell receptor phenotype have been reported. [33][34][35] This is now considered an immunophenotypic variant of the same disease entity in the World Health Organization (WHO) classification.…”

Primary Angiocentric T-Cell Intestinal Lymphoma with Epstein-Barr Virus in a 5-Year-Old Boy

“…In the present case we were not able to demonstrate reactivity for PF1 marker in the lymphomatous cells despite numerous attempts with different antigen retrieval procedures. Notably, FISH studies for the 7ql 1.23 and 7q3 1 regions and centromeric 8 chromosome failed to demonstrate the presence of 7q isochromosome and trisomy 8 in the present case, abnormalities consistently found in gamma/delta hepatosplenic T-cell lymphoma from a pediatric patient [10]. We do not regard the focal villous atrophy found in the present case as representing celiac disease in the child because less involved areas of the mucosa clearly exhibited normal villous/crypt ratio.…”

Chromosome 12p abnormalities in dysgerminoma of the ovary: a FISH analysis

“…12 We analyzed the spatial distribution of the green and red signals to detect the specific patterns of signal aggregation consistent with i(12p), as previously reported. [13][14][15][16] A classical seminoma specimen was used as a positive control for FISH analyses, and lymphocytes in dysgerminoma specimens were used for the negative control. The positive control specimen represented by a classical seminoma showed both overrepresentation of 12p and the presence of i(12p) in a small percentage of nuclei, while lymphocytes from the background of dysgerminomas were consistently negative for 12p overrepresentation and for i(12p).…”