Detection rate of pulmonary cytology in salivary gland type lung carcinomas - A territorial multicenter database analysis.

Salivary gland type lung carcinomas are rare. The detection rate of pulmonary cytology for these tumors is uncertain due to low tumor incidence. This study aims to detail the detection rate of pulmonary cytology by a territory wide healthcare database analysis in Hong Kong. Through a computerized Hong Kong healthcare database search, histologically confirmed pulmonary cytology reports of adenoid cystic carcinoma, mucoepidermoid carcinoma and myoepithelial carcinoma of 44 hospitals and institutions were retrieved, reviewed, reclassified to a 5-tier category (inadequate/C1, benign/C2, atypia/C3, suspicious/C4, malignant/C5) for analysis. From 1,442,936 specimens (492,254 patients), 295 specimens (92 patients, 53/57.61% male and 39/42.39% female) (0.02%) were included, with 119 bronchial, 16 lung, 150 sputum and 10 tracheal specimens. Histologic correlates were - mucoepidermoid carcinoma: 145/49.20%, adenoid cystic carcinoma: 140/47.50% and myoepithelial carcinoma: 10/3.40%. Cytologic diagnoses comprised of 56/19.00% C1, 168/56.90% C2, 30/10.20% C3, 13/4.40% C4 and 28/9.50% C5 cases. Detection rate was not affected by tumor type (p > 0.05), but was by sampling method with lung tissue aspirates significantly higher for than other specimen types (84.62%, p < 0.001). Sputum cytology was rarely positive (5.00%, p < 0.001). For bronchial cytology, atypia rate (C3-C5) was increased (37.61%, p = 0.011) but not for suspicious or above (C4-C5) (19.66%, p = 0.391), in contrast to it showing highest adequacy rate (98.32%, p < 0.001) not reflecting tumor detection. Lung aspiration appears to show improved detection rate in exfoliative specimens, while including a notable non-actionable atypia rate for bronchial cytology. Concurrent or early follow-up core biopsy can be considered for urgent diagnostic indications.