Non-contrast imaging characteristics of papillary renal cell carcinoma: implications for diagnosis and subtyping

Autor: Anand V, Badri, Nikhil, Waingankar, Kristin, Edwards, Alexander, Kutikov, Rosaleen B, Parsons, David Y, Chen, Marc C, Smaldone, Rosalia, Viterbo, Richard E, Greenberg, Robert G, Uzzo
Rok vydání: 2019
Předmět:
Zdroj: The Canadian journal of urology. 26(5)
ISSN: 1195-9479
Popis: Current radiographic guidelines suggest unenhanced renal lesions20 Hounsfield Units (HU) are overwhelmingly benign, requiring no further evaluation. We evaluate our experience with papillary renal cell carcinoma (pRCC) presenting with low pre-contrast attenuation and the relationship of attenuation with histologic pRCC subtype.We reviewed our institutional kidney cancer database for patients with pT1 or pT2 pRCC between 2003-2017. Tumors were categorized by papillary subtype by expert uropathologists. Preoperative CT images were analyzed at six regional tumor locations. Low, presumably benign, unenhanced median attenuation was defined as ≤ 20 HU. We calculated the frequency of pRCC with low attenuation and assessed the relationship between attenuation and pRCC subtype using logistic regression.Sixty-one patients with evaluable imaging were included. Median tumor size was 6 cm (1.7 cm-15.3 cm) with 39% (n = 24) type-1 and 61% (n = 37) type-2. Half of all pRCC tumors (n = 30) exhibited very low pre-contrast attenuation (20 HU), risking misdiagnosis as benign using current guidelines. Of these, 80% (n = 24) were type-2 with significant biological potential. Overall, type-2 tumors demonstrated a lower pre-contrast attenuation than type-1 (median HU: 19.8 (1.5-42.3) versus 29.6 HU (10-45.8), p0.01; max HU: 25.3 versus 36.5 HU, p0.01). After adjustment, lower pre-contrast HU was an independent predictor of pRCC subtype associated with a 5.5-fold increase of being type-2 (OR = 5.47, p0.01).pRCCs may exhibit very low attenuation on pre-contrast CT. This appears more common among the more aggressive type-2 subtype. These data suggest that low attenuation (20 HU) alone on non-contrast CT imaging is insufficient as a single parameter to rule out malignancy.
Databáze: OpenAIRE