The Residents’ Case of the Month is a resident‑selected and resident‑driven series highlighting interesting cases, ranging from common diagnostic findings to rare entities.
Epidermoid cyst is a subtype of prepubertal teratoma showing a stratified squamous epithelium lining without skin appendages or other elements. There was no associated GCNIS.
This case was contributed by Dr. Yaniv Hadi (PGY‑1).
February 2026
73 year old female with lung mass, incidental finding
Atypical adenomatous hyperplasia (AAH) is a small (usually ≤ 5 mm), localized proliferation of mildly to moderately atypical type II pneumocytes and/or club cells lining alveolar walls and sometimes respiratory bronchioles. Within the category of preinvasive lesions, AAH is a putative precursor of adenocarcinoma in situ (AIS).
This case was contributed by Dr. Yaniv Hadi (PGY‑1).
The provided cases were organized and uploaded by Fazilet Yilmaz, MD.