We have posted updated reviews of the following topics:Bone > Other tumors > Simple bone cyst
by Nasir Ud Din, M.B.B.S.
Topic summary: Cystic bone lesion, usually first 2 decades, with compatible radiological features; cyst lacks epithelial lining. Fibrin-like deposits in cyst wall organize and mineralize, forming immature and mature bone as well as cementum-like structure. IHC has no value.
Breast (malignant & nonmalignant) > Adenosis > Microglandular
by Julie M. Jorns, M.D.
Topic summary: Rare benign lesion of haphazard, irregularly distributed, small, uniform, rounded, open glands with eosinophilic secretions. Mimics invasive carcinoma due to infiltrative stromal growth and single epithelial layer devoid of myoepithelium. S100+, ER-, PR- but invasive ductal carcinoma is opposite.
Esophagus > Benign tumors > Squamous papilloma
by Yukihiro Nakanishi M.D., Ph.D.
Topic summary: Benign esophageal epithelial polyp composed of squamous epithelium with a papillary growth pattern and fibrovascular cores of lamina propria. Due to irritation, infection, genetics. Usually asymptomatic, found incidentally.
Kidney tumor > Benign adult tumors > Mixed epithelial and stromal tumor (MEST)
by Bonnie Choy, M.D.
Topic summary: Uncommon tumor of variable cystic and solid components with diverse epithelial and stromal elements. Part of continuum with adult cystic nephroma. Typically perimenopausal women, often with long term hormonal treatment. Mostly benign, stromal cells are ER+, PR+.
Lung nontumor > Other nonneoplastic disease > Amyloidosis
by Brian D. Stewart, M.D., Andras Khoor, M,D., Ph.D.
Topic summary: Presents as diffuse alveolar septal, nodular or tracheobronchial amyloidosis, all with characteristic amorphous material, Congo red+, bifrefringent with polarization. Usually due to AL deposition (associated with myeloma).