Pulmonary Cytology Flashcards
Adequacy of a lung sample is determined by. . .
. . . the presence of alveolar macrophages
Normal mesothelial cells
Usually seen as single cells, sometimes with rare clusters of ~10 cells.
Binucleation and multinucleation are common. Cytoplasm is dense with an abundance of tonofilaments. Cells classically display a “lacy” rim or halo, corresonding to microvilli present on the cell surface.
When reactive, cells may have significant nuclear atypia, but should still predominantly be seen a single cells. Prominent nucleoli may also be seen.
Note the “windows” between epithelial cells, a key feature of non-malignant mesothelial cells.
“Eosinophilic pleural effusion”
Considered “eosinophilic” when eosinophils account for at least 10% of the nucleated cells present.
Fun fact: if you refrigerate these specimens for >24 hours, you have a good shot at finding Charcot-Leyden crystals.
Can also be associated with: pneumothorax, recent procedure, hypersensitivity reaction, infection
Rheumatoid pleuritis
Abundant clumps of granular debris, numerous single and multinucleated macrophages.
Screening a pleural cytology specimen for metastatic thymoma
p63 is key here. It should be negative in mesothelial cells, but positive in thymus-derived epithelium.
Lupus pleuritis
The characteristic finding, shown here, is a macrophage or neutrophil containing a partially digested cell within its cytoplasm, called a “hematoxylin body.” The cell is called an “LE cell.”
Mesothelioma
Often described as “mulberry pattern,” and often (but not always) with preserved N:C ratio. Cytomegaly is often present, and villi are often disturbed or lost. Cytoplasm is often bubbly. Nuclear contour is often preserved.
Some blasphemous people will say that it is foolish to try and diagnose mesothelioma by morphology, and instead you should use calretinin, HBME-1, WT1, and D2-40 to confirm mesothelial differentiation and BAP1, MTAP, p16, and sometimes p53 to confirm malignant potential.
Differentiating metastatic carcinoma from mesothelial cells
Claudin-4 is key here
Primary effusion lymphoma
HHV8- or EBV-driven lymphoma primary to the pleura, peritoneal fluid, or pericardial fluid. Occurs in immunocompromised individuals.
Also CD30+, CD138+, multiple myeloma oncogene-1 and myc overexpressing.
Cells are large with round nuclei, coarsely granular chromatin, and a moderate amount of cytoplasm, often with an intensely basophilic periphery that gives a plasmacytoid appearance.
Rule of thumb for thinking about a cytologic diagnosis of mesothelioma
More, bigger cells in more, bigger clusters
Endosalpingosis
Cuboidal or columnar cells with bland nuclear features and cilia. May have Psammoma bodies and will be PAX8 positive.
Like endometriosis. . . just less symptomatic.
Bronchial reserve cell hyperplasia
Small, dark nuclei that show nuclear molding. However, they are extremely small (even smaller than small cell, about the size of a red blood cell).
There should never be any mitoses or single cell necrosis.
Curschmann’s spirals
Coiled strands of mucus that stains purple on Papanicolaou stain.
Have historically been associated with chronic respiratory diseases, but are nonspecific and no longer reported.
Ferruginous bodies
Charcot Leyden crystals
Herpes Simplex Virus
Note the clumping, molding, and peripheralization of the nuclei in this giant cell.
Respiratory Syncytial Virus
Note the distinct, separate, and dispersed nuclei of this giant cell.
CMV or Adenovirus
They are impossible to tell apart by morphology.
