Hürthle cell carcinoma: diagnostic and therapeutic implications

BACKGROUND: Hürthle cell carcinoma is a variant of follicular cell carcinoma of thyroid. It may present as a low-grade tumour or as a more aggressive type. Prognosis depends upon the age of the patient, tumour size, extent of invasion and initial nodal or distant metastasis. PATIENT AND METHODS: The case of Hürthle cell carcinoma is reported in a 79-year-old man who presented with a rapidly increasing lump on the left side of his neck, having had a right hemithyroidectomy for colloid goitre 24-years-ago. Fine needle aspiration cytology confirmed the presence of Hürthle cells, raising the possibility of a Hürthle cell neoplasm. The patient underwent staging and surgery. Histology showed Hürthle cell carcinoma and the patient underwent adjuvant therapy. The literature on Hürthle cell neoplasms is reviewed. CONCLUSIONS: Fine needle aspiration cytology may recognise Hürthle cell lesion but final diagnosis of carcinoma depends upon histological confirmation of vascular or capsular invasion. Staging and surgery in Hürthle cell carcinoma are similar to follicular carcinoma of thyroid with favourable outcome despite the controversy regarding the histological classification and adjuvant therapy. Elderly patients with Hürthle cell carcinoma need to be made aware of their poorer prognosis and should be offered more radical treatment

Photochemistry of Wild-Type and N378D Mutant E. coli DNA Photolyase with Oxidized FAD Cofactor Studied by Transient Absorption Spectroscopy.

International audienceDNA photolyases (PLs) and evolutionarily related cryptochrome (CRY) blue-light receptors form a widespread superfamily of flavoproteins involved in DNA photorepair and signaling functions. They share a flavin adenine dinucleotide (FAD) cofactor and an electron-transfer (ET) chain composed typically of three tryptophan residues that connect the flavin to the protein surface. Four redox states of FAD are relevant for the various functions of PLs and CRYs: fully reduced FADH(-) (required for DNA photorepair), fully oxidized FADox (blue-light-absorbing dark state of CRYs), and the two semireduced radical states FAD(.-) and FADH(.) formed in ET reactions. The PL of Escherichia coli (EcPL) has been studied for a long time and is often used as a reference system; however, EcPL containing FADox has so far not been investigated on all relevant timescales. Herein, a detailed transient absorption study of EcPL on timescales from nanoseconds to seconds after excitation of FADox is presented. Wild-type EcPL and its N378D mutant, in which the asparagine facing the N5 of the FAD isoalloxazine is replaced by aspartic acid, known to protonate FAD(.-) (formed by ET from the tryptophan chain) in plant CRYs in about 1.5 μs, are characterized. Surprisingly, the mutant protein does not show this protonation. Instead, FAD(.-) is converted in 3.3 μs into a state with spectral features that are different from both FADH(.) and FAD(.-) . Such a conversion does not occur in wild-type EcPL. The chemical nature and formation mechanism of the atypical FAD radical in N378D mutant EcPL are discussed