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Background: Fine‐needle aspiration (FNA) diagnosis of pancreatic serous cystadenoma (SCA) remains challenging. This retrospective study aimed to evaluate the roles of cyst fluid ancillary testing and combined fine‐needle biopsy (FNB) in improving the diagnostic yield. Methods: The authors retrospectively reviewed cytology cases that were histologically confirmed SCAs. Clinical features and FNA cyst fluid biochemical and molecular analysis results along FNB findings were reviewed. Results: The study cohort included 31 cases from 13 male and 18 female patients with a mean age of 65. The original cytologic diagnoses were nondiagnostic (n = 6, 19%), negative for malignant cells/cyst contents (n = 7, 23%), atypical cells (n = 3, 10%), nonmucinous cyst (n = 11, 35%), and serous cystadenoma (n = 4, 13%). Cyst fluid carcinoembryonic antigen (CEA) analysis was performed in 17 cases, all of which showed a low CEA level (<192 ng/mL). All 14 cases with molecular testing showed a wild‐type KRAS. Inhibin immunohistochemistry was retrospectively performed on the FNA cell blocks, inhibin was positive in six of seven cases tested. In 15 cases with concurrent FNA and FNB biopsies, the diagnosis of SCA was seen in only one FNA case (7%) but 13 FNB cases (87%). Conclusions: This study suggests that FNA diagnosis of SCA remains challenging even with ancillary testing including cyst fluid CEA level and KRAS mutation analysis. Adjunct inhibin immunostaining may help improve the cytologic diagnosis of selective SCA cases. FNB appears superior to FNA for a definite diagnosis of SCA. Cytologic diagnosis of pancreatic serous cystadenoma remains challenging. Ancillary cyst fluid analysis, adjunct inhibin immunohistochemistry, and additional fine‐needle biopsy sampling help improve diagnostic yield. [ABSTRACT FROM AUTHOR]

Context.--Salivary gland-type tumors (SGTs) of the lung represent a distinct group of lung neoplasms. Pulmonary SGTs often pose diagnostic challenges, especially in small biopsy and cytology samples because of limited sample volume and overlapping morphology among pulmonary SGTs, metastatic SGTs of head and neck origin, and other lung tumors. Objective.--To identify the clinical characteristics, histomorphology, immunophenotypic features, and molecular alterations that are crucial for the diagnosis and differential diagnosis of pulmonary SGTs, especially in small biopsy and cytology specimens. Data Sources.--Literature review and authors' personal practice experience. Conclusions.--An accurate diagnosis of pulmonary SGTs can be achieved by careful evaluation of clinical findings and histomorphology in conjunction with immunohistochemical studies and molecular analysis. (Arch Pathol Lab Med. 2021;145:1379-1386; doi: 10.5858/arpa.2021-0093-RA), Salivary gland-type tumors (SGTs) arising outside of the head and neck areas are uncommon and have been described in the breast, skin, cervix, trachea, and lung. (1) Pulmonary SGTs represent [...]