NSCLC - Pictures Flashcards
Moderate squamous cell dysplasia
Cellular atypia is observed at the midpoint of the mucosa. This includes hyperchromasia and elevated mitotic rate.
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Well-differentiated squamous cell carcinoma of the lung
Displays areas of keratinization and easily identifiable intercellular bridges. Nuclei are small and nucleoli are inconspicuous. Necrosis is usually absent or may be focally present.
Moderately-differentiated squamous cell carcinoma of the lung
May have areas of keratinization and intercellular bridging, but has more extensive areas of hemorrhage and necrosis. Mitotic figures and cellular pleomorphism are more prominent.
Poorly-differentiated squamous cell carcinoma of the lung
May be lacking in definitive evidence of squamous differentiation, or it may be only focally present. Tendency to grow in sheets. Extensive hemorrhage and necrosis.
Small cell variant of squamous cell carcinoma of the lung
This can be tricky, and SCV-SCC is always on the ddx for true small cell, and vice-versa.
Ways to differentiate:
- IHC : SCV-SCC will be keratin5/6 and p63 positivity, while true SCC will stain for neuroendocrine markers instead.
- Chromatin : True SCC will have salt-and-pepper chromatin, while SCV-SCC will have a more basaloid cell chromatin pattern
- Focal keratinization or squamous features suggest SCV-SCC over true SCC.
Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH).
Often seen in the background of carcinoid tumors, however its incidence in the general population is unclear.
Sclerosing pneumocytoma (WSI-23-19-7)
Benign lung neoplasm with features of pneumocytic differentiation with dual-cell population. Usually well circumscribed with a capsule. Rarely may metastasize to lymph nodes, but even then the prognosis is excellent.
2 cell types make up the tumor:
1. Small, cuboidal cells with hobnail nuclei lining papillary stalks
2. Large, round to polygonal stromal cells with clear cytoplasm in solid areas
May have associated large vessels or extensive hyalinized fibrosis.
Lymphoepithelial carcinoma
Tumor cells growing in nests and cords with an intervening fibroblastic and dense lymphoplasmacytic stroma. Looks a lot like a node with prominent sinus histiocytes. . . but a little too disorganized, and the sinus histiocytes should NOT be dividing.
Comedo necrosis, syncytial cells, and large cells with cherry red nucleoli may be present.
Often EBV associated, EBER ISH positive.
Atypical adenomatous hyperplasia
“An adenomatous lesion no more than 0.5 cm in diameter”
Precursor lesion to BAC and pulmonary adenocarcinoma.
Histologically, may be indistinguishable from bronchoalveolar carcinoma.
Fibroelastosis
Seen in irradiated sites in the lung. If you see this near a tumor bed and the patient has a history of radiation therapy, it is worth mentioning.
Atypical adenomatous hyperplasia
“A focal lesion, 5 mm or less in diameter, in which the involved alveoli and respiratory bronchioles are lined by monotonous, slightly atypical cuboidal to low columnar epithelial cells with dense nuclear chromatin, prominent nucleoli and scant cytoplasm”
Intranuclear pseudoinclusions are a helpful hint.
The earliest precursor to adenocarcinoma. Once part of “bronchioalveolar carcinoma”, now renamed.
Pulmonary adenocacinoma-in-situ
Composed of columnar cells that proliferate in a lepidic growth pattern. The neoplastic cells are well-differentiated.
Stromal, vascular, and pleural invasion or any necrosis disqualify this diagnosis and upgrade the lesion to invasive adenocarcinoma. Also, because MIA exists as a category, you cannot diganose these on biopsy or frozen section – only on permanent.
Formerly “bronchioalveolar carcinoma”
Minimally invasive adenocarcinoma
The earliest progression of AIS to invasive carcinoma. By definition, must be less than 3 centimeters in size with either pure lepidic growth or predominant lepidic growth and ≤ 5 mm of stromal invasion.
It is really the allowance of a small degree of stromal invasion that separates this diagnosis from AIS.
Like AIS, there must be no lymphatic, vascular or pleural invasion and no tumour necrosis.
Colloid variant adenocarcinoma
Like mucinous, often TTF-1 negative and may show enteric markers.
Fetal variant adenocarcinoma
