Rosai Chapter 11 - Pleura Flashcards
(45 cards)
Classic gross presentation of malignant mesothelioma
Multiple gray or white ill-defined nodules in a diffusely thickened pleura
Frequency of Mesothelioma
Epithelioid > Biphasic/mixed > Sarcomatoid
a subtype of sarcomatoid mesothelioma accompanied by abundant deposition of fibrous tissue demonstrating a storiform or “Patternless pattern of Stout” arrangement of neoplastic spindle cells
Desmoplastic mesothelioma
Histologic features helpful in separating desmoplastic mesothelioma from benign fibrous proliferations (4)
- invasion of chest wall soft tissue or lung parenchyma
- bland necrosis
- frankly sarcomatoid areas with cytologic atypia
- characteristic storiform growth pattern in the context of random variation
Features in favor of malignancy versus from a reactive mesothelial hyperplasia (6):
- Stromal invasion
- Full-thickness involvement
- Expansile nodules
- Random variation in cellularity
- Architectural complexity
- irregular distribution of vessels
Malignant Mesothelioma / Adenocarcinoma:
-Substantial number of columnar-shaped cells
Adenocarcinoma
Malignant Mesothelioma / Adenocarcinoma:
-Cellular crowding
Adenocarcinoma
Malignant Mesothelioma / Adenocarcinoma:
-Nuclear molding
Adenocarcinoma
Most reliable criterion for distinguishing malignancy from reactive mesothelial hyperplasia
Stromal invasion
Most useful for distinguishing epithelioid mesotheliomas from metastatic carcinoma, particularly in small biopsies
Immunostains
Account for the majority of cases presenting with a pseudomesotheliomatous growth pattern and is therefore the most likely primary site in the absence of a history of prior or concomitant extrathoracic malignancy
Lung adenocarcinoma
More sensitive than calretinin for sarcomatoid mesothelioma
antibodies to podoplanin (ie. D2-40, antipodoplanin)
Most common recurrent somatic mutations in malignant mesothelioma which target 3 genes functioning as tumor suppressors:
- cyclin-dependent kinase inhibitor 2A (CDKN2A)
- BRCA1-associated protein 1 (BAP1)
- Neurofibromin 2 (merlin) (NF2)
Useful diagnostic tool for separating benign from malignant mesothelial proliferations
homozygous deletion of p16
Solitary fibrous tumor with Hypoglycemia
Doege-Potter syndrome
Hypoglycemia in Doege-Potter syndrome is due to secretion of __ by neoplastic cells
insulin-like growth factor II
Characteristics of malignant SFT (4)
- increased cellularity
- cytologic atypia (nuclear hyperchromasia and pleomorphism)
- Mitoses
- Necrosis
Differential diagnosis of the more sclerotic types of SFT (3):
- Fibrous plaque
- Fibromatosis (desmoid tumor)
- Calcifying fibrous pseudotumor
Relatively sensitive IHCs for diagnostically challenging SFT cases
- STAT6 (diffuse nuclear)
- CD34
- BCL2
fusion between the two pleural layers
pleural symphysis
secondary to pneumothorax of any cause
Reactive eosinophilic pleuritis
Asbestos is a family of fibrous hydrated silica that are divided into two groups:
- Serpentines
- Amphiboles
Main pleural manifestations of asbestos exposure (3):
- pleural plaques
- pleural fibrosis
- mesothelioma
Fiber types found in most cases of asbestos-related mesothelioma
- Amosite
- Crocidolite
