21 Histopathology Flashcards
Histo features of JNA
Unencapsulated admixture of vascular tissue and fibrous stroma where the vessel walls lack elastic fibers and have decreased to no smooth muscle; mast cells are abundant in the stroma
Cell of origin of parotid gland SCCa
Excretory duct cell
What feature distinguishes low grade from high grade mucoepidermoid CA
The amount of mucin in the tumor
What are the histologic differences b/w a hemangioma and a vascular malformation
Cellular proliferation is characteristic of hemangiomas; vessel dilation is characteristic of vascular malformations
What are the histologic features of vascular malformations
Dilated, ectatic vascular channels with a nl endothelial lining and areas of thrombosis
What are the typical histologic characteristics of lymphatic malformations
Multiple dilated lymphatic channels lined by a single layer of epithelium
What cells are unique to Hodgkin’s lymphoma
Reed-Sternberg cells
What are the main histo types of RMS
embryonal, alveolar, pleomorphic
What is m/c type of RMS in H&N
embryonal
What are the characteristic histo findings of RRP
Exophytic papillary fronds of multilayered benign squamous epithelium containing fibrovascular cores; cytologic atypia, in particular, koilocytotic atypia, is not unusual
What test is used to dx IFS
tissue bx
What are the histo findings of IFS
Hyphae with tissue invasion and noncaseating granulomas
What feature seen on renal bx with EM is pathognomonic for Alport syndrome
basket-weave configuration of the glomerular basement membrane
What other test can be useful in dx Alport syndrome
skin bx
What histo finding distinguishes cholesteatoma from CHL granuloma
squamous epithelium is present only in cholesteatoma
What cell patterns are characteristic of vestibular schwannoma
Antoni A (tightly arranged) Antoni B (loosely arranged)
In which pattern are Verocay’s bodies found?
Antoni A
T/F: Tumors with high percent of Antoni A cells relative to Antoni B cells have a better prognostic outcome
False: Outcome is independent of cell proportions
How does one differentiate b/w a benign and malignant paraganglioma
There are no clear histologic characteristics of malignancy; malignant lesions are defined by the presence of mets
What are the 2 primary cells of paragangliomas
Type I granule-storing chief cells and type II schwann-like sustentacular cells (S-100 +) arranged in a cluster called a Zellballen
What are the histo features of BCCa of skin
Clefting, lack of intracellular bridges, nuclear palisading, and peritumoral lacunae
What histo characteristic of recurrent BCCa has negative prog significance
Irregularity in peripheral palisade
What are the histo features of SCCa of skin
Keratin pearls in well-diff lesions
Poorly diff lesions may require IHC with cytokeratin or vimentin
What are the levels defined in Clark’s system
Level I: Epidermis.
Level II: Invasion of basal lamina into the papillary dermis.
Level III: Fill the papillary dermis.
Level IV: Invasion into the reticular dermis.
Level V: Invasion into subcutaneous fat.
