115th Annual Meeting of the United-States-and-Canadian-Academy-of-Pathology (USCAP), San-Antonio, Kuzey Mariana Adaları, 21 - 26 Mart 2026, cilt.106, (Özet Bildiri)
Eosinophilic vacuolated tumor (EVT) is described in the 2022 World Health Organization classification as an emerging renal tumor with TSC1/TSC2/MTOR mutation(s). Approximately 60 clinically indolent cases have been reported. However, we have encountered EVTs with potentially aggressive morphologic features. The frequency and clinical significance of these findings remain unknown and prompted the current study.
Design
Through multi-institutional collaboration, 36 EVTs resected between 2004 and 2025 were evaluated for worrisome morphologic features including invasion into large vessels, fat, the pelvicalyceal system, or lymphatic/small vessels, as well as increased mitotic activity, necrosis and large size (≥7 cm). EVTs were diagnosed using established diagnostic features, including eosinophilic cells with prominent cytoplasmic vacuoles and nucleoli plus immunohistochemistry (CD117, KRT7, KRT20, CD10 and/or cathepsin K). In a subset of EVTs, somatic tumor testing for TSC1/TSC2/MTOR variants was performed. Events (metastasis, recurrence, progression, and disease-specific death), treatment received, and clinical status at last follow-up were collected via review of the electronic patient records.
Results
Patient age ranged from 13 to 80 years (median 51). The M:F ratio was 1:1.8. EVTs were resected by partial (n=22) or radical (n=14) nephrectomy, with tumor size ranging from 1.1 to 15.5 cm (median 2.7). Eleven of 13 sequenced EVTs had a TSC1 (n=2), TSC2 (n=5) or MTOR (n=4) mutation. One additional patient had clinically suspected tuberous sclerosis. Seven of 36 (19.4%) EVTs had worrisome morphologic features (Table 1): 5 tumors measured ≥7 cm, 3 showed fat invasion (Figure 1), 2 had large vessel invasion (Figure 2), and 2 invaded lymphatic/small vessels. No increased mitotic activity or necrosis was identified. Median follow-up time for 17 patients was 12 months (range 1-67). One patient had regional lymph node (LN) metastases at nephrectomy with no progression on follow-up. Another patient with no nodal disease at presentation developed regional and distant LN metastases 9 and 24 months post nephrectomy, respectively. All patients were alive at last follow-up.
Figure 1 - 846
Figure 2 - 846
Conclusions
Worrisome morphologic features including vascular invasion, fat invasion and/or large tumor size can be seen in up to one fifth of EVTs, some of which may be associated with metastatic potential, at least to local lymph nodes. The clinical significance of such findings warrants further validation with longer follow-up.
