Granulosa thecal cell tumour in a mare causing hypertrophic osteopathy

Abstract

Summary Hypertrophic osteopathy (HO) is a rare condition in the horse characterised by symmetrical proliferation of connective tissue and subperiosteal bone, along the diaphyses of limb bones. In this case, a 10‐year‐old Irish Draught cross Thoroughbred mare was presented for investigation of weight loss, lethargy and firm swelling of all 4 distal limbs. Radiographs of the distal limbs revealed palisade‐like periosteal new bone formation perpendicular to the cortex of the distal third metacarpal and metatarsal bones, proximal (P1) and mid (P2) phalanges. Rectal examination revealed a mass of approximately 20 x 30 cm in the right caudoventral abdomen. The mare was diagnosed with HO due to a granulosa thecal cell (GTC) tumour. The GTC tumour was removed and the diagnosis confirmed on histological examination. Clinical examination and radiographs of the distal limbs after surgery demonstrated reduction in size of the limb swellings and new bone formation. To the authors' knowledge this is the first report of HO due to a GTC tumour in a mare.

Diagnosis of Granulosa Cell Tumors in Arabian Mares by Ultrasonography, Hormonal Profile and Histopathology

“…GCT found to be the most common ovarian tumor in mares that represents about 2.5-6% of all equine tumors (Crabtree et al, 2013). In this study, mares with GCT aged between 4-15 years old were presented with a history of stallion like-behavior, prolonged anestrous, maiden mares had a well-developed clitoris and this result was discussed previously by Packer and McKane, 2012. Most of the mares affected with GCT are middle-aged; however, GCT has been reported in mares of all ages, including neonates, older foals and yearlings (Sherlock et al, 2016). Granulosa cell tumor more commonly occurs in middle-aged mares or older and have been rarely reported in mares younger than 4 years old.…”

“…There is no characteristic clinical manifestation for GTCT, and a variety of clinical signs may be present, depending on the severity of the disease (Patrick et al, 2003). Mares with GTC tumors usually present with behavioral abnormalities, abdominal discomfort and irregular estrus cycle (Packer and McKane, 2012). Mares affected with GTCT often exhibit irregular estrous cycles characterized by either anestrus or nymphomania; stallion-like behavior or aggressiveness is common (Frederico et al, 2007).…”

Ascites in a 13‐year‐old miniature horse mare with an ovarian granulosa theca‐cell tumour: A manifestation ofMeigs' syndrome?

“…). GCTs have also been reported in conjunction with hypertrophic osteopathy (Packer and McKane ), obstruction of the small colon (Mair ), and haemoperitoneum (Gatewood et al . ; Alexander et al .…”

“…They often present as an enlarged ovary with typical clinical behavioural changes in mares, including abnormal cycling patterns and stallion-like behaviour (Clark 1975;Stickle et al 1975;McCue et al 1998). GCTs have also been reported in conjunction with hypertrophic osteopathy (Packer and McKane 2012), obstruction of the small colon (Mair 2002), and haemoperitoneum (Gatewood et al 1990;Alexander et al 2004). Also recently described are 2 cases in which GCTs had significant adhesions to other abdominal organs (Rambags et al 2003), and while they have been diagnosed primarily in nongravid mares, a recent report documents the management of GCT during pregnancy (Crabtree et al 2013).…”