Predicting malignant involvement in a thyroid nodule: role of ultrasonography.

OBJECTIVE: To assess how ultrasonography can contribute during the evaluation of a thyroid nodule and whether this technique can have a role in predicting malignant involvement. METHODS: In this retrospective study, data were analyzed on 220 consecutive patients (with 348 thyroid nodules) who underwent thyroidectomy and had previously undergone assessment by high-resolution thyroid ultrasonography. Nodule size, echogenicity, regularity of margins, halo sign, presence or absence of calcifications, and invasion of surrounding tissues were evaluated. The nodules were classified as low, medium, or high risk for malignant involvement on the basis of nodule characteristics found on ultrasonography. All nodules were submitted to cytologic examination by fine-needle aspiration (FNA) before thyroidectomy. Ultrasound, FNA, and pathologic postoperative results were compared. RESULTS: Among the 348 thyroid nodules, 56 were ultrasonographically classified as low risk, 268 as medium risk, and 24 as high risk for malignant potential. Fifty of 56 (89.3%) low-risk nodules and 213 of 268 (79.5%) medium-risk nodules were diagnosed as benign at pathologic postoperative examination. In contrast, however, only 6 of 24 (25%) high-risk nodules were diagnosed as benign. Among the 18 high-risk nodules of 1-cm diameter or larger, FNA showed a 20% false-negative result. CONCLUSION: High-risk classification of a thyroid nodule on ultrasonography had a positive predictive value for malignant involvement of 75%. Nodule characteristics analyzed by ultrasonography should be considered at the time of surgical intervention.

[Slight hormonal alterations in a patient with a large pheochromocytoma]. / Mínimas alterações hormonais em paciente com grande feocromocitoma.

We present a case report that the patient had symptoms suggesting pheochromocytoma, a large tumor (> 50 g) and a single minimally altered laboratorial test, exemplifying a diagnostic pitfall. A 31 y.o. male patient had two acute abdominal events, the last one accompanied by headache, arterial hypertension, facial flushing, perspiration and cutaneous pallor. In another admission, the patient had sustained arterial hypertension and cardiac arrhythmia. From laboratory analysis, the vanililmandelic acid was slightly modified. Scintigraphy disclosed a large adrenal mass suggesting pheochromocytoma. Histopathology confirmed this hypothesis. This report points out that patients with symptoms suggesting pheochromocytoma, even when plasma catecholamines and urinary metanephrines levels are normal, may harbor large tumors with a high catecholamines turnover or that had undergone hemorrhagic necrosis.

Mínimas alterações hormonais em paciente com grande feocromocitoma / Slight hormonal alterations in a patient with a large pheochromocytoma

Relatamos caso clínico no qual o paciente apresentou sintomas sugestivos de feocromocitoma, grande tumor (maior que 50 g) e mínima alteração laboratorial, exemplificando uma armadilha diagnóstica. Um homem de 31 anos apresentou dois episódios de abdômen agudo, sendo o último acompanhado por cefaléia, hipertensão arterial, rubor facial, sudorese e palidez cutânea. Em outra internação, o paciente apresentava hipertensão arterial sustentada e arritmia cardíaca. Em relação aos testes laboratoriais, apenas o ácido vanil-mandélico foi levemente alterado. Cintilografia com MIBG foi realizada e sugeriu a presença de grande massa adrenal compatível com feocromocitoma. Uma amostra histopatológica da peça foi obtida após cirurgia e confirmou esta hipótese. Esse caso sugere que em pacientes que possuem sintomas sugestivos de feocromocitoma, mesmo com valores normais de catecolaminas plasmáticas e metanefrinas urinárias, devemos considerar as possibilidades de um grande tumor metabolizando catecolaminas em seu interior ou que sofreu necrose hemorrágica.