Lab 1 Flashcards
Main differences squamous cell carcinoma and normal squamous epithelium in esophagus?
- normal epithelium: orderly process of maturation from basal layer to outside getting pinker; well differentiated cells; no surface keratin; mitosis only in the basal and parabasal layers of cells
- in carcinoma: keratin pearls, more densely stained nuclei, mitosis can occur everywhere
What is the “desmoplastic” reaction?
- desmoplasia = stromal response to tumor invasion; proliferation of fibroblasts around cancer cells
2 features that distinguish a carcinoma as being squamous cell type?
- extracellular keratin/keratin pearls
2. intercellular bridges
Gross characteristics of squamous cell carcionma?
firm and tan or white
whiteness corresponds to quantity of keratin
tumor margins unencapsulated and usually infiltrative
What is chronic gastritis?
presence of chronic mucosal inflammatory changes + inflammatory cells leading to mucosal atrophy and intestinal metaplasia
How does chronic gastritis manifest on histology?
- gastric glands surrounded by lymphocytes, plasma cells, and sometimes eosinophils
- lymphoid follicles in basal mucosa
Where does adenocarcinoma always begin from?
always begins from the mucosa
What is structure of adenocarcinoma on histology?
- dilated glandular structures
- OR secretion of mucin, goblet cells
How do you differentiate well-differentiated adenocarcinoma from normal gastric mucosal glands?
normal mucosa has ordered arrangement of identical vertically-oriented glands
tumor glands vary in size/shape; bigger nuclei; densely stained
What determines early or advanced gastric carcinoma?
advanced = invasion deeper than submucosa
What is histology of signet ring cell?
cell with intracellular accumulation of mucin
compresses nucleus to the side to form semilunar shape
What kind of polarity are signet ring cells?
no polarity and no gland-like structures = very poorly differentiated
What features of signet ring cell adenocarcinoma make it difficult to achieve a biopsy diagnosis?
- signet ring tumors do not form discrete mass
- can camouflage well with surrounding mucosal cells
What 3 special stains to highlight adenocarcinoma tumor cells?
- PAS
- mucicarmine
- alcian blue
all stain for mucin
What happens to gastric mucosa/submucosa in lymphoma?
- massively expanded so create giant rugal folds
What is consistency of lymphoma?
- soft consistency = fish flesh because lack desmoplastic stroma
How do you describe tumor border of lymphoma?
“pushing” [rather than infiltrative]
How does lymphoma differ from adenocarcinoma grossly?
lymphomas soft, tan fleshy and lack desmoplastic stroma; borders well-demarcated rather than infiltrative
What is MALT lymphoma?
mucosa associated lymphoid tissue = arises from mucosal B cells
What organism linked to MALT lymphoma of the stomach?
H pylori –> if give antibiotics can get tumor regression
How do carcinoid tumors appear on histology?
- solid tumor nests look like jigsaw puzzles
- lack glandular features
- nuclei round, uniform
How do you distinguish carcinoid tumors from adenocarcinomas?
carcinoids = discrete sheets or small nests of tumor cells w/ rounded borders; each nest surrounded by fibrotic stromo; cells monotonous, round, unifomrly spaced, salt and pepper pattern of chromatin
adenocarcinomas: grow haphazardly, cells pleomorphic, nuclei vary in size and shape, lack speckling, more mitotic, glands/mucin
What feature of nuclear chromatin is characteristic of neuroendocrine tumors?
nuclei have coarsely speckled salt and papper chromatin
What stains to confirm diagnosis of carcinoid tumor?
silver stains [argyrophil or argentaffin] show cytoplasmic neuroendocrine granules of carcinoid as fine black dots
or use antibodies: chromogranin, synaptophyisn, neuron-specific enolase
