Ultrasonographic features of adrenal gland lesions in dogs can aid in diagnosis

Abstract

BackgroundUltrasonography to visualize adrenal gland lesions and evaluate incidentally discovered adrenal masses in dogs has become more reliable with advances in imaging techniques. However, correlations between sonographic and histopathological changes have been elusive. The goal of our study was to investigate which ultrasound features of adrenal gland abnormalities could aid in discriminating between benign and malignant lesions. To this end, we compared diagnosis based on ultrasound appearance and histological findings and evaluated ultrasound criteria for predicting malignancy.ResultsClinical records of 119 dogs that had undergone ultrasound adrenal gland and histological examination were reviewed. Of these, 50 dogs had normal adrenal glands whereas 69 showed pathological ones. Lesions based on histology were classified as cortical adrenal hyperplasia (n = 67), adenocarcinoma (n = 17), pheochromocytoma (n = 10), metastases (n = 7), adrenal adenoma (n = 4), and adrenalitis (n = 4). Ultrasonographic examination showed high specificity (100%) but low sensitivity (63.7%) for identifying the adrenal lesions, which improved with increasing lesion size. Analysis of ultrasonographic predictive parameters showed a significant association between lesion size and malignant tumors. All adrenal gland lesions >20 mm in diameter were histologically confirmed as malignant neoplasms (pheochromocytoma and adenocarcinoma). Vascular invasion was a specific but not sensitive predictor of malignancy. As nodular shape was associated with benign lesions and irregular enlargement with malignant ones, this parameter could be used as diagnostic tool. Bilaterality of adrenal lesions was a useful ultrasonographic criterion for predicting benign lesions, as cortical hyperplasia.ConclusionsAbnormal appearance of structural features on ultrasound images (e.g., adrenal gland lesion size, shape, laterality, and echotexture) may aid in diagnosis, but these features alone were not pathognomic. Lesion size was the most direct ultrasound predictive criterion. Large and irregular masses seemed to be better predictors of malignant neoplasia and lesions <20 mm in diameter and nodular in shape were often identified as cortical hyperplastic nodules or adenomas.

Suspected bilateral adrenal gland tumour causing primary Addison’s disease in a dog

“…However, FNA does not differentiate cortical adenomas from carcinomas [13]. Nevertheless, adrenal gland size, irregularity, and vascular invasion with possible metastatic spread indicated malignancy [2]. Thus, in this report, a primary bilateral adrenal gland tumour spreading to caudal vena cava, portal lymph nodes, and liver was anticipated.…”

“…For further evaluation of the nature of the mass of the tumour, further diagnostics (fine needle aspiration [FNA] or histology) were discussed but also declined. Yet, imaging studies had revealed several criteria indicating malignancy [2] and thus made malignant neoplasia the most likely diagnosis. However, differentials to neoplasia such as fungal disease or granuloma could not be excluded.…”

Incidental Adrenocortical Carcinoma in Dogs: Clinical, Tomographic and Histopathological

“…Cães e gatos com tumor em adrenal podem ter sintomatologia mais branda ou apresentar sinais clínicos severos, portanto esses achados devem ser classificados quanto ao comportamento biológico e funcionalidade [6,13]. Em estudo recente se observou prevalência maior em cães idosos e de raça definida [17]. A ausência de sinais clínicos, alterações bioquímicas séricas e eletrolíticas compatíveis, sugerem afuncionalidade da neoplasia.…”

“…Nos exames de imagem, a aparência e tamanho da massa são os principais fatores preditores da malignidade [19]. Outros achados ultrassonográficos descritos na literatura incluem aumento irregular e lesões em adrenais direita a neoplasias malignas, bem como 82,3% de carcinomas adrenocorticais apresentaram forma nodular (único ou múltiplo) em ultrassonografia abdominal [17]. Recomenda-se ressecção cirúrgica principalmente em crescimentos acima de 6 cm, porém a decisão deve se basear também no aspecto da massa, idade do paciente e outras condições pré-existentes [10,16].…”

“…Um estudo recente avaliou pacientes submetidos a tomografia computadorizada sem suspeita de massa, doença em adrenal ou sinais clínicos compatíveis com hiperadrenocorticismo adrenal-dependente, e demonstrou prevalência de incidentalomas adrenais de 9,3% [4]. Outro estudo comparou alterações ultrassonográficas de glândulas adrenais de cães com as alterações encontradas em histopatológico e foi visto que em carcinomas adrenocorticais a ultrassonografia detectou variação em tamanho e forma em aproximadamente 65% dos casos [17].…”