Prostatic Localization of a Migrating Grass Awn Foreign Body in a Dog

Abstract

A 13-year-old male mixed-breed dog was examined because of hematuria and pyrexia. Ultrasonographic examination of the genitourinary tract showed the presence of a migrating grass awn in the right prostatic lobe. Laparotomy allowed, under ultrasonographic guidance, to remove entirely the migrating grass awn from the prostatic parenchyma. The recovery was uneventful and four months after the surgery the owner reported that the dog showed the complete resolution of the clinical signs and full return to normal activity. To our knowledge, this case report describes for the first time the clinical presentation, imaging findings, management and outcome for a dog with prostatic localization of a migrating grass awn.

An unusual presentation of a migrating grass awn in a dog and a review of the imaging modalities used to diagnose and determine the extent of disease

“…have also been reported in the literature and are native to the United States 3,5,7,8,14,19 . Possible routes of entry for grass awns have been described in the literature including inhalation, ingestion and percutaneous migration 1,3–6,8–10,12,14–24 . The grass awn's fusiform shape, consisting of a pointed floret and backward facing barbs, allows for attachment to the animal's hair coat and unidirectional migration through body tissues propelled by the body's movement 1,3–6,8–10,14–24 .…”

“…The grass awn's fusiform shape, consisting of a pointed floret and backward facing barbs, allows for attachment to the animal's hair coat and unidirectional migration through body tissues propelled by the body's movement 1,3–6,8–10,14–24 . It creates a foreign body response and introduces bacteria as it migrates until it becomes lodged or exits the body 1–3,5–8,11,12,16,21,23,24 . Common sites for sequestration and abscessation are the pulmonary parenchyma, bronchi, the pleural space or the sublumbar musculature via migration along the diaphragmatic crura 1–3,7–9,16,17,19,20 .…”

“…Common sites for sequestration and abscessation are the pulmonary parenchyma, bronchi, the pleural space or the sublumbar musculature via migration along the diaphragmatic crura 1–3,7–9,16,17,19,20 . Less commonly reported sites of migration include the spinal cord, the brainstem, the intraocular space, the lacrimal sac, the retrobulbar space, the tricuspid valve, the urinary bladder, pericardial space, prostate, the duodenal papilla and the celiac artery 1–7,12,16,17,20,21,23–26 . Clinical signs are often non‐specific and vary depending on the migration path of the grass awn.…”

“…Various imaging modalities can be employed to aid in the diagnosis. Ultrasonography is commonly the initial modality of choice due to the fact that it is readily available, non‐invasive and can be performed without general anaesthesia 1,3,12,23,30 . The ultrasonographic features of a grass awn have been extensively described in the literature.…”

“…The ultrasonographic features of a grass awn have been extensively described in the literature. Typically, grass awns appear as a spindle‐shaped structure with two or three hyperechoic linear interfaces with an occasional hypoechoic centre and acoustic shadowing 1,3–5,11,12,18,20,21,27,28,31 . The presence of acoustic shadowing, however, is dependent on the size of the grass awn, the depth of the focal zone and the transducer frequency used 1,3–5,18,28,30,31 .…”