Computed tomographic appearance of canine thyroid tumours.

Abstract

OBJECTIVES: To describe the computed tomography features of canine thyroid tumours. METHODS Retrospective study of records of dogs with a thyroid tumour and neck computed tomography. Neck computed tomographies were evaluated for tumour characteristics. Thoracic radiographs and computed tomographies were evaluated for lung nodules. RESULTS: Of 19 identified cases, 17 were carcinomas and 2 were adenomas; 12 had mineralisation, 16 had heterogeneous attenuation and 16 were unilateral. Tumours were located from the temporomandibular joint to C5. Sixteen had well-defined margins postcontrast. Tumours were ovoid and mean volume was 57·4 cm(3) . By computed tomography, eight had definitive or possible invasion into surrounding structures; all eight were histopathologically invasive carcinomas. Five histopathologically non-invasive tumours and two adenomas had no computed tomography invasion into surrounding structures. Four had complete palpable mobility (two adenomas and two histopathologically invasive carcinomas); one had computed tomography evidence of possible invasion. The sensitivity of palpable mass mobility to determine histopathological invasion was 71% with 0% specificity. The sensitivity of computed tomography invasion to determine histopathological invasion was 70% with 100% specificity. CLINICAL SIGNIFICANCE: Computed tomography scans revealed several common features. Palpable mass mobility was not definitive for lack of histopathological invasion. Computed tomography invasion was specific but not very sensitive for histopathological invasion.