Session: SUN 303-321-Cancer in Endocrine Tissues
Bench to Bedside
Poster Board SUN-321
Material and methods. We performed a prospective study at a university hospital and studied 12 patients with GEP-NETs and possible subcutaneous metastases detected on routine abdominal CT scans to determine the differential characteristics of subcutaneous nodules secondary to administration of SSA. Patients underwent high-resolution and color Doppler sonography, cytology (5 patients), and biopsy (4 patients). Mean group values were compared using one-way ANOVA or a Kruskal-Wallis test. Strength of association was evaluated with Spearman’s correlation test.
Results. Mean age was 61.3 ± 11.9 years. Five patients were male and 7 were female. Median number of nodules was 6 ± 5 per patient. Three patients were on octreotide LAR, 7 lanreotide Autogel, and 2 had received both SSA. CT scan findings were nonspecific: all nodules had poorly defined borders with hazy changes in the adjacent subcutaneous fat. Sonography revealed a different pattern from subcutaneous metastases and showed a correlation between echogenicity of the nodule and time of administration of SSA: a hyperechoic pattern was found in recent injections (less than 3 months after the depot injection) (p<0,05) and a hypoechoic pattern in long-term injections (more than 3 months) (p<0,05). Hypoechogenic lesions were frequently surrounded by a characteristic hyperechoic peripheral rim with decreased transmission. This rim was lost in long-standing nodules. On Color Doppler only mild peripheral vascularization was found in hypoechoic lesions. Cytology demonstrated characteristic acellular proteinaceous material. Biopsy showed a granulomatous reaction with epithelioid cells and foreign body giant cells around the acellular proteinaceous material.
Conclusions. Although CT scans are nonspecific, sonography is very useful for the differential diagnosis of subcutaneous nodules secondary to treatment with SSA. Cytology is a minimally invasive procedure with considerable diagnostic potential. Biopsy should be reserved for rare cases in which a definitive diagnosis has not been reached.
Nothing to Disclose: JR, AP, BC, JF, SI, ED, MM
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