title: Regression of subcutaneous lymphoma following removal of an ovarian granulosatheca cell tumor in a horse.
abstract: A 9-year-old Arabian mare was admitted for evaluation of multiple subcutaneous nodules and infertility. Fine-needle aspiration of one of the subcutaneous nodules resulted in a cytologic diagnosis of histiolymphocytic lymphoma. Palpation per rectum and transrectal ultrasonography revealed a mass associated with the left ovary. Excision of the ovarian tumor was performed, and a histopathologic diagnosis of granulosa-theca cell tumor was made. After removal of the granulosa-theca cell tumor, subcutaneous nodules regressed. The referring veterinarian reported that the nodules had also disappeared and then recurred after administration of a synthetic progestin. To further characterize the lymphoma and investigate this possible hormonal relationship, immunophenotyping and estrogen and progesterone receptor assays were performed. The subcutaneous lymphoma was classified as a T-cell rich B-cell lymphoma, results of estrogen receptor assays were negative, and results of progesterone receptor assays were positive. Clinical observations of subcutaneous lymphoma in horses indicate that the waxing and waning nature of these tumors may be associated with the estrous cycle, pregnancy, foaling, and lactation. Clinical observations and identification of progesterone receptors suggest that a relationship between serum steroid hormone concentrations, such as estrogen and progesterone, and subcutaneous lymphoma may exists.
authors.affiliation: Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610-0125, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Henson
authors.forename: A R
authors.initials: AR
authors.lastname: Alleman
authors.forename: T J
authors.initials: TJ
authors.lastname: Cutler
authors.forename: P E
authors.initials: PE
authors.lastname: Ginn
authors.forename: L C
authors.initials: LC
authors.lastname: Kelley
mesh_terms: D000818:Animals; D001707:Biopsy, Needle / Q000662:veterinary; D005260:Female; D006106:Granulosa Cell Tumor / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D006734:Horse Diseases / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006736:Horses; D008228:Lymphoma, Non-Hodgkin / Q000473:pathology / Q000503:physiopathology / Q000662:veterinary*; D009364:Neoplasm Recurrence, Local / Q000209:etiology / Q000662:veterinary; D009365:Neoplasm Regression, Spontaneous; D009378:Neoplasms, Multiple Primary / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D010051:Ovarian Neoplasms / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D010507:Periodicity; D045167:Progesterone Congeners / Q000627:therapeutic use; D011980:Receptors, Progesterone / Q000032:analysis; D013798:Thecoma / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D014204:Trenbolone Acetate / Q000031:analogs & derivatives / Q000627:therapeutic use
chemical_list: D045167:Progesterone Congeners; D011980:Receptors, Progesterone; C023445:altrenogest; D014204:Trenbolone Acetate