Combined use of fine-needle aspiration biopsy, MIBI scans and frozen section biopsy offers the best diagnostic accuracy in the assessment of the hypofunctioning solitary thyroid nodule.
OBJECTIVE
The probability of malignancy is increased in hypofunctioning solitary thyroid nodules (HFNs). Fine-needle aspiration biopsy (FNA), (99m)Tc-methoxyisobutylisonitrile (MIBI) and frozen section biopsy (FS) have limited independent diagnostic accuracy for the differential diagnosis of HFNs. The goal of this study was to assess the accuracy of the three independent diagnostic methods in distinguishing between benign and malignant disease.


METHODS
A total of 130 patients with an HFN on the (99m)Tc-pertechnetate scan were included in this study. FNA, MIBI scans, FS, thyroidectomy and histological analysis of surgical specimens for final diagnosis were performed in all patients.


RESULTS
Of the 130 patients, 80 (61.54%) had benign lesions and 50 (38.46%), malignant lesions. FNA was diagnostic in 78/130 (60%) patients and non-diagnostic in 52/130 (40%) patients. None of the patients with a negative MIBI scan had a final histological diagnosis of malignancy, and MIBI scans were negative in 38.46% of patients with non-diagnostic FNA results. FS was diagnostic in 104/130 (80%) patients and non-diagnostic in 26/130 (20%) patients. Sensitivity, specificity, positive and negative predictive values and positive and negative likelihood ratios were 81.3%, 97.8%, 96%, 88%, 36.95 and 0.19 respectively for FNA; 100%, 61.3%, 61.7%, 100%, 2.58 and 0 respectively for MIBI; and 80.5%, 100%, 100%, 89%, 0 and 0.2 respectively for FS. Use of both MIBI scans and FS in patients with non-diagnostic FNA rendered a specificity and sensitivity of 100%.


CONCLUSIONS
MIBI scans exclude malignancy in a significant proportion of patients with non-diagnostic FNAs (38% in this study). Cystic nodules with a positive MIBI scan should be further investigated even when the FNA result indicates a benign lesion. Combined use of FNA, MIBI and FS offers the best diagnostic accuracy.
Hurtado-López
Luis Mauricio
LM
Thyroid Clinic, General Hospital of Mexico, Dr. Balmis 148, Colonia Doctores, 06720 México City, México.
Arellano-Montaño
Sara
S
Torres-Acosta
Evelyn Migdalia
EM
Zaldivar-Ramirez
Felipe Rafael
FR
Duarte-Torres
Reyna Margarita
RM
Alonso-De-Ruiz
Patricia
P
Martínez-Duncker
Iván
I
Martínez-Duncker
Carlos
C
D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle / Q000379:methods*; D003598:Cytoskeletal Proteins; D005260:Female; D005629:Frozen Sections / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology*
D048868:Adaptor Proteins, Signal Transducing; C540426:CMIP protein, human; D003598:Cytoskeletal Proteins; D019275:Radiopharmaceuticals