Table 2 Summary features of the new, emerging and provisional renal entities, their current WHO status and GUPS classification proposals.
Type | Clinical features | Morphology | IHC | Molecular features | Prognosis | Currently in WHO/Status | GUPS proposal | |
|---|---|---|---|---|---|---|---|---|
Eosinophilic solid and cystic RCC (ESC RCC) | Mostly females, ≤10% in TSC patients | Solid and cystic, voluminous eosinophilic cells, cytoplasmic coarse granularity | CK20+, CK7−, CD117−, vimentin+, cathepsin K+ | Somatic bi-allelic loss or mutations of TSC1 and TSC2 | Good, rare cases aggressive (5–10%) | No | Novel entity | |
RCC with fibromyomatous stroma (RCC FMS) | No specific clinical features, ≤10% in TSC patients | Fibromyomatous stroma (mostly peripheral) and clear cell areas with elongated, frequently branching tubules, focal papillary morphology can be seen | CK7+, CAIX+, CD10+, vimentin+ | TSC1/MTOR mutations, some with ELOC1 (TCEB1) mutations and monosomy 8, no VHL mutations | Usually favorable | Yes /Emerging/provisional entity | Novel entity | |
Eosinophilic vacuolated tumor (EVT) | F > M, wide age range, rare in TSC patients, typically smaller, mahogany brown | Solid, eosinophilic (oncocytic) cells with frequent, large cytoplasmic vacuoles, prominent nucleoli | cathepsin K+/−, CD117+/−, CK7+ in only rare cells, CK20-, vimentin- | TSC/MTOR mutations, loss of chr. 19 and 1 | No aggressive behavior documented(limited data) | No | Emerging entity | |
Low-grade oncocytic tumor (LOT) | Older patients, solitary, non-syndromic, smaller, tan to brown | Solid growth, “oncocytic look”, sharp transition to edematous areas, round to oval nuclei (low-grade), often with perinuclear halos | CD117− (rarely weak+), CK7+, FOXI1− | Diploid, deletions of chr. 19p, 19q and 1p, TSC/MTOR mutations (limited data) | Good | No | Provisional entity | |
Anaplastic lymphoma kinase rearrangement-associated RCC (ALK-RCC) | Adults (younger middle age or older), pediatric with sickle cell trait, medullary location | Diverse (variable admixed patterns), often mucinous/myxoid background, medullary carcinoma--like morphology in children | ALK+, PAX8+, otherwise non-specific, rare cases TFE3+ in children (without translocation) | ALK rearrangement in all (various fusion partners) | Adverse prognosis (MS, death) in about 25% | Yes/emerging/provisional entity | Novel entity | |
Thyroid-like follicular RCC (TLFRCC) | F > M, wide age range, tan to brown, low stage | Exclusive follicular pattern, variable size follicles, cuboidal/ low columnar lining cells, colloid-like luminal material | TTF1− thyroglobulin−, PAX8+, CK7+ (otherwise non-specific) | Variable (limited data) | Usually non-aggressive, rare cases with MS | Yes/emerging/ provisional entity | Emerging entity | |
Atrophic kidney-like lesion (AKLL) | Young adults, discrete mass, brown nodule, no specific clinical features | Follicular growth, atrophic tubules and stroma in between atrophic lining cells, luminal eosinophilic fluid, calcifications, thick capsule | Follicle lining cells are WT1+, PAX8−, CK7−, TTF1−, thyroglobulin− | Limited data | Good (likely non-neoplastic lesion) | No | Provisional entity | |
Biphasic hyalinizing psammomatous RCC (BHP RCC) | Older adults, M»F, non-syndromic (only 8 cases reported) | Solid and papillary growth, biphasic cell population: larger cells and smaller cells clustered around basement membrane material (“glomeruloid pattern”) | PAX8+, CK7+ | Somatic mutations of NF2 | Minimal F/U (one patient progressed with MS and died) | No | Provisional entity | |
