Cytological Diagnosis of Rare Synchronous Primary Malignancies

Abstract

Introduction: Synchronous tumours are rare. The defining criteria is the occurrence of more than one tumour simultaneously or within a span of six months, having different histology and involving different organs. Similarly, distinction of a metastatic lesion from the primary tumour is imperative and has diagnostic and prognostic implications. Here we report of rare occurrence of polymorphous low-grade adenocarcinoma (PLGA) of minor salivary gland of cheek and diffuse sclerosing variant of papillary thyroid carcinoma (DSVPTC) in a 70-year-old female diagnosed at fine needle aspiration cytology (FNAC). Case report: A 70-year female presented with swelling over the right side of the cheek and left lobe of thyroid for 3 months. Cheek swelling was 4 x 4 cm, well defined, firm and with smooth external surface. Thyroid swelling left sided 3 x 3 cm, solitary and firm to hard. FNAC from the cheek swelling showed papillae, acini, nuclear crowding, overlapping, fine chromatin, nuclear clearing, nuclear grooving and basement membrane material favouring a diagnosis of low-grade epithelial malignancy possible PLGA. Thyroid FNAC smears showed typical features of papillary thyroid carcinoma (PTC) along with areas of extensive squamous metaplasia. Diagnosis of both the cases were confirmed at histopathology. Conclusions: Synchronous malignant tumours of head and neck region is rare. Both PLGA and DSVPTC show common features like papillae formation, nuclear features and squamous metaplastic cytoplasm. Accurate diagnosis of these lesions is challenging at cytology. Cytopathologist should be aware of this novel entity to avoid misdiagnosis and plan proper management.

Keywords

• synchronous
• minor salivary gland tumours
• cytomorphology
• multiple primary malignancies.