title: Sclerosing paraganglioma of the carotid body: a potential pitfall of malignancy.
abstract: Paragangliomas (PGs) of the head and neck region are typically benign, slow-growing neuroendocrine tumours. At times, they may exhibit unusual histological features, such as prominent stromal sclerosis (sclerosing PG), which may raise concerns of malignancy. We describe a case of sclerosing PG of the carotid body, emphasizing the value of immunohistochemical stains for differential diagnosis. A 43-year-old woman presented with a painless lump on the neck. A magnetic resonance imaging scan demonstrated a hypervascular lesion of the carotid body, which was surgically excised. Grossly, the lesion measured 1.8 cm at maximum diameter. On microscopic examination, irregular nests and tiny bundles of neoplastic cells were found between thick bands of fibrous tissue. Focal nuclear cytomegaly and marked pleomorphism were noted. Neoplastic cells proved to be immunoreactive for chromogranin, synaptophysin and neuron specific enolase, but negative for cytokeratins, smooth muscle actin and CD34. Ultrastructurally, numerous mitochondria, rough endoplasmic reticulum structures and endocrine granules were seen in the cytoplasm of the tumour cells. On consideration of the above-mentioned clinico-pathological and ultrastructural findings a diagnosis of sclerosing PG was established. Sclerosing PG is a rare entity which may mimic a malignant neoplasm. The recognition of this unusual morphological variant of PG, together with appropriate immunostains, leads to the correct diagnosis.
authors.affiliation: Division of Pathological Anatomy, Department of Surgery and Translational Medicine, University of Florence, Largo Brambilla, 3, 50134, Florence, Italy, raffaella.santi@yahoo.it.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Santi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Franchi
authors.forename: Valeria
authors.initials: V
authors.lastname: Saladino
authors.forename: Massimo
authors.initials: M
authors.lastname: Trovati
authors.forename: Giovanna
authors.initials: G
authors.lastname: Cenacchi
authors.forename: Massimo
authors.initials: M
authors.lastname: Squadrelli-Saraceno
authors.forename: Gabriella
authors.initials: G
authors.lastname: Nesi
mesh_terms: D000328:Adult; D002345:Carotid Body Tumor / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology*; D002864:Chromogranins / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D012598:Sclerosis / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D002864:Chromogranins; D016708:Synaptophysin; D010751:Phosphopyruvate Hydratase