Computed Tomography and Magnetic Resonance Imaging of an Epidermoid Cyst in a Foot of a Horse

Multi‐modality imaging of aggressive submural neoplasia of the hoof in two horses

“…Keratomas, osteomyelitis, epidermoid cysts and osseous cyst-like lesions are some of the more commonly described differentials for distal phalangeal osteolysis with a space occupying mass. 3,[12][13][14][15][16][17][18][19][20] The radiographic appearance of these pathologies is generally well documented in the literature. 3,[12][13][14][15][16][17][18][19][20] Keratomas are one of the more commonly encountered causes of distal phalangeal osteolysis in equine practice.…”

“…3,[12][13][14][15][16][17][18][19][20] The radiographic appearance of these pathologies is generally well documented in the literature. 3,[12][13][14][15][16][17][18][19][20] Keratomas are one of the more commonly encountered causes of distal phalangeal osteolysis in equine practice. They are caused by hyperplasia of the keratin producing cells of the stratum germinativum at the coronary band or the secondary epidermal laminae of the hoof wall which then create a space occupying mass.…”

“…12 Developmental pathologies such as osseous cyst-like lesions and epidermoid cysts are more commonly located centrally or eccentrically within the distal phalanx and are generally characterised by the presence of spherical, well-defined regions of osteolysis with or without surrounding sclerosis. 14,16,20 Space occupying lesions of the hoof wall will often be identified when the horse is presented for farriery or lameness examination. Radiography is the most common imaging modality utilised for the assessment of regional osseous involvement however additional use of advanced imaging modalities such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) is becoming more commonplace, particularly in the more complicated cases that are refractory to initial treatment.…”

“…21 This information can also assist with biopsy and surgical planning. 3,16,22,23 Although aggressive hoof wall neoplasia is rare, there are certain imaging features which may raise our index of suspicion for an aggressive submural lesion. This case report documents two horses with similar radiographic findings that underwent advanced imaging, multiple surgeries and hoof wall resections for therapeutic and diagnostic reasons with a final diagnosis of malignant neoplasia.…”

“…This is often identifiable radiographically but is not pathognomonic for a malignant process with other, more common pathologies also known to cause distal phalangeal osteolysis. Keratomas, osteomyelitis, epidermoid cysts and osseous cyst‐like lesions are some of the more commonly described differentials for distal phalangeal osteolysis with a space occupying mass 3,12–20 . The radiographic appearance of these pathologies is generally well documented in the literature 3,12–20 …”