A Fifty year old female patient reported to the hospital with complaint of swelling in the lower jaw since 4-5 months. On clinical examination, a swelling was seen below the left side of the angle of the mandible which was measuring 5 x 3cm and extending 4cm below the base of the mandible and obliquely 5cm from the angle of the mandible. The mass was just anterior and deep to the sternocleidomastoid muscle [Figure 1]. On palpation it was soft in consistency, fluctuant and painful. An The FNAC was performed in a municipal hospital which was diagnosed as mucoepidermoid tumor of parotid and was negativity for Koch bacilli. The FNAC report did not mention the detailed findings. Based on these findings the patient was operated on and the excised tissue was grossed. The gross finding showed that the tissue was measuring 5 x 3 cm and cut section was partially brownish in colour. The specimen showed mucoid material within the cystic cavity, the cyst wall was very thick with papillary projections [Figure 2]. The tissue was formalin fixed, processed, sectioned and stained with haematoxylin and eosin.
Histopathological findings showed cystic cavity lined by epithelium and the underlying connective tissue showed germinal centres. The cystic epithelium was thrown into folds at various places. The epithelium was stratified squamous epithelium type and was 6-8 cells layered thick [Figure 3]. The rete ridges were flat. At some places the epithelium was separated from the underling connective tissue. The cystic lumen showed some squamous epithelial strands which were desquamated from the cystic epithelium. The underlying connective tissue showed abundant lymphoid tissue with many germinal centres. Some fibrous connective tissue elements with fibroblasts and blood vessels lined by endothelial cells were evident. [Figures 4-6]. To rule out tuberculosis Ziehl-Neelsen stain was previously done and there was no evidence of Koch bacilli. Based on all these findings a final diagnosis of infected branchial cyst was given. She underwent complete excision of the lesion with preservation of the facial nerve. The patient recovered well and had no recurrence at 1-year of follow up.