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⭕Ameloblastoma (follicular and plexiform patterns) 🔬Epithelial islands with peripheral palisading of columnar cells and central stellate reticulum-like cells in a fibrous stroma ☢Well-defined radiolucency around the crowns of impacted molars with partial cortical resorption

🧬NAB2-STAT6 fusion (intrachromosomal rearrangement on 12q) ☢️Well-circumscribed pleural-based mass, mostly attached to visceral pleura; may grow large enough to fill a hemithorax and displace the mediastinum

🧬At least 30% hereditary: SDH genes (most common), NF1, VHL, RET, MAX, EPAS1, FH; SDHB IHC screens for SDH loss ☢️Marked T2 hyperintensity ("light bulb sign"); no signal drop on opposed-phase MRI, unlike lipid-rich adenoma

⭕oncocytoma 🔬Nests and tubules of cells with abundant granular eosinophilic cytoplasm and small round regular nuclei, floating in edematous stroma 🧪c-kit+; CK7- 🧬Loss of chromosome 1, 11q13 rearrangement, deletion of chromosome 14 ☢️Central scar may be seen on CT

⭕ Acquired cystic disease-associated RCC 🔬 Arises in ACKD. Eosinophilic cells with prominent nucleoli and cytoplasmic vacuoles giving a sieve-like pattern; intratumoral calcium oxalate crystals. ☢️ small atrophic kidneys studded with cysts + heterogeneously enhancing solid mass

🧬KRAS mutation in most cases (~80–90%), clustered in exon 2 codon 12 (mainly G12V); no trisomy 7/17. Indolent behavior ☢️Small, round, well-defined renal mass with high attenuation on pre-contrast CT (arrow)