Temporary spontaneous regression of feline non-Hodgkin's lymphoma

A 6-year-old neutered male British Shorthair cat presented with two rapidly growing subcutaneous masses, one over each thoracic wall. High-grade, non-Hodgkin's lymphoma was confirmed following histopathology, immunohistochemistry and PCR analysis for antigen receptor re-arrangements. Following biopsy there was rapid regression of the remaining neoplastic tissue with no medical treatment. The cat relapsed 3 months later, with poor response to therapy, and was euthanased.

Spontaneous regression (SR) of cancer is a rare occurrence and is uncommonly reported in veterinary species. To the author's knowledge this is the first reported case of SR of non-FeLV-related feline, high-grade non-Hodgkin's lymphoma.