Pediatric testicular follicular lymphoma
B-CELL CLONALITY: positive
B-Cell Receptor PCR (BIOMED-2):
IgH (VDJ) FR1: Polyclonal
IgH (VDJ) FR2: Clonal (281bp)
IgH (VDJ) FR3: Polyclonal
IgK-DE: Clonal (280bp, 286bp)
FISH FOR BCL-2 REARRANGEMENT: Negative.
DIFFERENTIAL DIAGNOSIS: follicular hyperplasia in the course of chronic orchitis.
Primary testicular lymphomas are rare in children with only few case reports of pre-B lymphoblastic lymphoma, Burkitt and Burkitt-like lymphoma, diffuse large B-cell lymphoma and follicular lymphoma. The case reported here represents a rare example of pediatric testicular follicular lymphoma. This tumor shows biological features that are different from the classic adult follicular lymphomas, lacking the BCL2/IGH translocation. By immunohistochemistry, the germinal center cells have a B-cell phenotype (CD20 positive) with expression of CD10 and Bcl6 proteins, but are Bcl2 protein negative. Similar to our case, published cases report that molecular genetic studies reveal immunoglobulin heavy chain (IGH) gene rearrangements , with no rearrangement involving the BCL2 gene [2, 3, 4, 5].
The most important differential diagnosis is with follicular hyperplasia in the course of chronic orchitis. The diagnosis of pediatric testicular follicular lymphoma should always be considered if there is back to back follicular growth pattern and no clinical or histologic evidence of infectious diseases with lack of inflammation or granulomas in the epididymis and non-affected testis. EBV and other infections process should be used to exclude, and the detection of a monoclonal Ig gene rearrangement can be helpful [2, 5].
Pediatric testicular follicular lymphomas have been reported to be a localized disease. The clinical outcome is excellent with treatment, including complete surgical resection and short duration chemotherapy or by surgical excision alone .
Contributed by Claudia Maria Salgado MD, PhD and Miguel Reyes-M˙gica MD