Carbonic anhydrase 4 and crystallin α-B immunoreactivity may distinguish benign from malignant thyroid nodules in patients with indeterminate thyroid cytology.

BACKGROUND: Thyroid nodules are present in 19%-67% of the population and carry a 5%-10% risk of malignancy. Unfortunately, fine-needle aspiration biopsies are indeterminate in 20%-30% of patients, often necessitating thyroid surgery for diagnosis. Numerous DNA microarray studies including a recently commercialized molecular classifier have helped to better distinguish benign from malignant thyroid nodules. Unfortunately, these assays often require probes for >100 genes, are expensive, and only available at a few laboratories. We sought to validate these DNA microarray assays at the protein level and determine whether simple and widely available immunohistochemical biomarkers alone could distinguish benign from malignant thyroid nodules. METHODS: A tissue microarray (TMA) composed of 26 follicular thyroid carcinomas (FTCs) and 53 follicular adenomas (FAs) from patients with indeterminate thyroid nodules was stained with 17 immunohistochemical biomarkers selected based on prior DNA microarray studies. Antibodies used included galectin 3, growth and differentiation factor 15, protein convertase 2, cluster of differentiation 44 (CD44), glutamic oxaloacetic transaminase 1 (GOT1), trefoil factor 3 (TFF3), Friedreich Ataxia gene (X123), fibroblast growth factor 13 (FGF13), carbonic anhydrase 4 (CA4), crystallin alpha-B (CRYAB), peptidylprolyl isomerase F (PPIF), asparagine synthase (ASNS), sodium channel, non-voltage gated, 1 alpha subunit (SCNN1A), frizzled homolog 1 (FZD1), tyrosine related protein 1 (TYRP1), E cadherin, type 1 (ECAD), and thyroid hormone receptor associated protein 220 (TRAP220). Of note, two of these biomarkers (GOT1 and CD44) are now used in the Afirma classifier assay. We chose to compare specifically FTC versus FA rather than include all histologic categories to create a more uniform immunohistochemical comparison. In addition, we have found that most papillary thyroid carcinoma could often be reasonably distinguished from benign disease by morphological cytology findings alone. RESULTS: Increased immunoreactivity of CRYAB was associated with thyroid malignancy (c-statistic, 0.644; negative predictive value [NPV], 0.90) and loss of immunoreactivity of CA4 was also associated with malignancy (c-statistic, 0.715; NPV, 0.90) in indeterminate thyroid specimens. The combination of CA4 and CRYAB for discriminating FTC from FA resulted in a better c-statistic of 0.75, sensitivity of 0.76, specificity of 0.59, positive predictive value (PPV) of 0.32, and NPV of 0.91. When comparing widely angioinvasive FTC from FA, the resultant c-statistic improved to 0.84, sensitivity of 0.75, specificity of 0.76, PPV of 0.11, and NPV of 0.99. CONCLUSIONS: Loss of CA4 and increase in CRYAB immunoreactivity distinguish FTC from FA in indeterminate thyroid nodules on a thyroid TMA with an NPV of 91%. Further studies in preoperative patient fine needle aspiration (FNAs) are needed to validate these results.

Gastrointestinal and hepatic manifestations of sarcoidosis.

Sarcoidosis is a multisystem disease characterized by noncaseating granulomas in the affected organs, including skin, heart, nervous system, and joints. Diagnosis of sarcoidosis is generally based upon a compatible history, demonstration of granulomas in at least two different organs, negative staining and culture for acid fast bacilli, absence of occupational or domestic exposure to toxins, and lack of drug-induced disease. Involvement of the hollow organs is rare. Rather than being due to sarcoidosis, some reported mucosal lesions may simply have incidental granulomas. Extrinsic compression from lymphadenopathy can occur throughout the gastrointestinal tract. The stomach, particularly the antrum, is the most common extrahepatic organ to be involved, while the small bowel is the least common. Liver involvement frequently occurs and ranges from asymptomatic incidental granulomas to portal hypertension from granulomas in the portal triad, usually with relatively preserved liver function. CT scans show hepatosplenomegaly and adenopathy, followed in frequency by focal low-attenuation lesions of the liver and spleen. Ascites is usually a transudate from right heart failure (because of pulmonary hypertension) or portal hypertension (because of biliary cirrhosis). Rarely, an exudative ascites may occur from studding of the peritoneum with nodules. Pancreatic involvement presents as a mass, usually in the head or a diffusely firm, nodular organ. Corticosteroids should be instituted when organ function is threatened, usually lungs, eyes, and central nervous system. Their role in the treatment of hepatic sarcoidosis is unclear. The overall prognosis is good although most patients will have some permanent organ impairment. Cardiac and pulmonary diseases are the main causes of death.