Polymorphous Adenocarcinoma: A Cytological Enigma Unveiled Through Uncommon Locations-A Case Study

Area of Science:

• Pathology
• Cytopathology
• Oncology

Background:

• Polymorphous adenocarcinoma (PAC) predominantly occurs in minor salivary glands but can present in major salivary glands, posing diagnostic challenges.
• Its overlapping clinical and microscopic features with other salivary gland tumors complicate diagnosis, with fine-needle aspiration (FNA) and core biopsy findings often being limited.

Purpose of the Study:

• To investigate the cytomorphological characteristics of polymorphous adenocarcinoma (PAC).
• To focus on the diagnostic challenges and features of PAC in uncommon anatomical locations, including major salivary glands.

Main Methods:

• A retrospective, single-institutional study analyzing 11 cases of PAC over four years.
• Cytological slides stained with Papanicolaou (Pap) and May-Grunwald Giemsa (MGG) were reviewed.
• Clinical details, procedure types, cell block material, immunocytochemistry, and histopathology/immunohistochemistry of follow-up specimens were analyzed.

Main Results:

• Eleven cases of PAC were identified, with seven in major and four in minor salivary glands.
• Histopathological correlation was achieved in 73% of cases; 27% were lost to follow-up.
• Cytology revealed hypercellular smears with uniform cells, branching papillae, sheets, and clusters, often with myxohyaline stroma. Lymph node metastasis and soft tissue infiltration were observed in some cases.

Conclusions:

• Cytological evaluation of PAC, especially in unusual sites, is challenging due to morphological variability and overlap with other neoplasms.
• Careful sampling, comprehensive assessment, and ancillary techniques are crucial for accurate diagnosis and effective management of PAC.
• Improved diagnostic accuracy can lead to better patient outcomes and a deeper understanding of this rare malignancy.