Solitary lymphatic cysts in neck of adults is a very rare clinical entity, as 90% cases of cystic hygromas are present in children below 2 years. Most of the solitary cystic hygromas in adults are benign and complete surgical excision is the preferred treatment. However, in all patients above 40 years of age, a solitary cystic lesion in neck must be thoroughly investigated to rule out presence of malignancy such as occult metastasis from papillary carcinoma of thyroid or squamous cell carcinoma arising from Waldeyer’s ring. We present a case of solitary lymphatic neck cyst in adult, along with a comprehensive review of the literature.