Low power: Pap stain
Loosely cohesive clusters and single cells with round to oval eccentric nuclei and moderate amounts of granular cytoplasm.
High power: Pap stain
Plasmacytoid cells with round to oval eccentric nuclei, salt and pepper chromatin and moderate amounts of granular cytoplasm.
Cell block H&E stain
Plasmacytoid cells with round to oval eccentric nuclei, salt and pepper chromatin and moderate amounts of granular cytoplasm.
Low power: DQ stain
Cellular smear showing loosely cohesive and singly dispersed cells.
High power: DQ stain
Plasmacytoid cells with round to oval eccentric nuclei and moderate amounts of granular cytoplasm.
High power: DQ stain
Plasmacytoid cells with round to oval eccentric nuclei and moderate amounts of granular cytoplasm.
Features
• Loosely cohesive and single cells, clusters and rosettes
• Monotonous uniform plasmacytoid cells
• Moderate well defined cytoplasm with neurosecretory granules
• May have oncocytic or clear cell change
• Round to oval, occasional spindled nuclei
• Eccentric nuclei (plasmacytoid)
• Stippled (salt and pepper) chromatin
• Small inconspicuous nucleoli
Low grade neuroendocrine tumors are also referred to as carcinoids. The main feature that separates typical carcinoids from atypical carcinoids and small cell carcinoma (SCC) or large cell neuroendocrine carcinoma (LCNEC) is the mitotic rate and necrosis: typical carcinoid rare mitosis (<2/10 HPF) with no necrosis; atypical carcinoid occasional mitosis (2-10/10HPF) with mild to moderate necrosis; LCNEC and SCC frequent mitosis (>10/10HPF) with abundant necrosis.
• Mitotic figures rare to absent
• No necrosis
• Express cytokeratin, synaptohysin, chromogranin, CD56, usually TTF-1 positive
• Use Ki-67 to grade tumor
Horan DC et al.Anal Quant Cytol. 1982 Jun;4(2):105-9.
Kim K et al. Diagn Cytopathol. 1986 Dec;2(4):343-6.
Szyfelbein WM et al.Diagn Cytopathol. 1988 Mar;4(1):1-8.