title: Thyroid cyst wall atypia in a patient with a history of malignant melanoma: a pitfall in fine-needle aspiration cytology.
abstract: We present an interesting case report from a patient with a history of desmoplastic malignant melanoma (MM), who presented with a thyroid nodule. The patient's clinical diagnosis included a benign thyroid nodule versus a primary thyroid malignancy or metastatic MM. Fine-needle aspiration biopsy showed highly atypical spindle cells suspicious for metastatic MM. The acellular cell block prevented further studies such as immunohistochemical analysis. The patient underwent surgical excision of the mass, which showed a benign cystic thyroid nodule with an atypical cyst lining. Here, we report the presence of atypical cyst-lining cells in a patient with diagnosis of MM. The atypical cytology of the cyst-lining cells has been reported in the English literature; however, presence of significant cytological atypia, especially in a patient with a history of another malignancy, can be problematic. The cytopathologist should be aware of this entity and its diagnostic pitfalls.
authors.affiliation: Department of Pathology, University of California, San Diego, California, USA.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Johnson
authors.forename: Farnaz
authors.initials: F
authors.lastname: Hasteh
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration; D006044:Goiter, Nodular / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology* / Q000601:surgery; D011859:Radiography; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000473:pathology; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery