Cytomorphology and diagnostic pitfalls of sebaceous and nonsebaceous salivary gland lymphadenoma: A multi‐institutional study

Abstract

Background Salivary gland lymphadenoma (LAD) is a rare benign neoplasm comprising sebaceous (SLAD) and nonsebaceous (NSLAD) types. Despite established histologic criteria, limited data on cytomorphology, tumor heterogeneity, and overlap with other entities make the diagnosis of LAD by fine needle aspiration (FNA) challenging. We describe a multi‐institutional cohort of 14 LADs with cytology, clinical, radiologic, and histopathologic data. Methods Our cohort included nine SLAD and five NSLAD with corresponding histopathology. Mean patient age and M:F ratio were 60.4 years (range 45‐86 years) and 1:2 for SLADs and 57.4 years (range 42‐80 years) and 1:1.5 for NSLADs, respectively. One NSLAD patient had a germline predisposition for Cowden syndrome. Glass slides and whole slide images of air‐dried Diff‐Quik (DQ), alcohol‐stained Papanicolaou smears (Pap) and cellblocks were reviewed for key cytomorphologic findings. Results FNAs from SLAD and NSLADs demonstrated vacuolated and basaloid epithelial clusters within a lymphoid background. Vacuolated cells from SLAD showed sebaceous cells with microvesicular cytoplasm indenting a central nucleus. Vacuolated cells from NSLAD were columnar with eccentric nuclei, corresponding to abluminal glandular cells. SLADs were classified using the Milan System for Reporting Salivary Gland Cytopathology as nondiagnostic (11.1%), nonneoplastic (44.4%), atypia of uncertain significance (AUS) (22.2%), and salivary gland neoplasm of uncertain malignant potential (SUMP) (22.2%). NSLADs were classified as AUS (40%), SUMP (40%) and Benign Neoplasm (20%). Conclusion Although rare, knowing the cytologic features of salivary LAD is important to avoid diagnostic pitfalls. Vacuolated cells can be prominent in both SLAD and NSLAD aspirates. Diagnostic issues arise from insufficient sampling of all tumor components leading to marked variation in diagnostic classification of LAD.

Correlation of Fine Needle Aspiration Cytology and Histopathological Evaluation in Salivary Gland Masses: A Single Center Retrospective Study

“…It may be reported in the "non-diagnostic" category (3,25). Insufficient material ratios have been reported in many studies with variable values such as 1.1% and 12% (2)(3)(4)(5)(6)(23)(24)(25)(26)(27)38). The inadequate rate in our study, which was slightly higher than in the literature, can be resolved by performing FNAC by an experienced radiologist/clinician and a rapid on-site evaluation until experience is gained.…”

Cytopathology of benign sebaceous salivary gland neoplasia: Comparison of two analogous yet dissimilar entities

“…47 Interestingly, this system fails to even list SLA in either of these categories, 48 basaloid features have been described in several prior studies of SLA. 4,7,14 A review of 33 previously reported FNA cases of SLA with demographic data shows that only 3 were specifically interpreted as SLA, 7,19,26 and 2 as possible SLA; a summary is shown in Table 2. 11,13 Another SLA series of two cases from Vazmitsel et al is not included in this table as they did not specifically declare their FNA interpretation for each case, nor did they include patient demographic information.…”

“…Compared to all SG neoplasms, those with basaloid features are more apt to be classified into either the salivary gland neoplasm of uncertain malignant potential (SUMP) category or the suspicious for malignancy category using the Milan system for reporting SG cytopathology (MSRSGC) 47 . Interestingly, this system fails to even list SLA in either of these categories, 48 yet cells with basaloid features have been described in several prior studies of SLA 4,7,14 . A review of 33 previously reported FNA cases of SLA with demographic data shows that only 3 were specifically interpreted as SLA, 7,19,26 and 2 as possible SLA; a summary is shown in Table 2 11,13 .…”

“…No case series of SA cytopathology could be found in our review of the Englishlanguage literature. Nonetheless, a single multi-institutional case series (nine cases) 4 and a number of single and dual case reports of SLA have been reported. We present the FNA biopsy findings from two examples of benign sebaceous neoplasia-one SA and one SLA-and discuss the cytomorphological features and diagnostic challenges associated with each.…”