obsolete medullary carcinoma

Medullary carcinoma, also known as medullary thyroid carcinoma (MTC), is a rare and distinct subgroup of thyroid cancers. When it comes to the differential diagnosis of MTC, several conditions need to be considered.

Key Conditions to Consider

• Hürthle cell neoplasia: This condition can exhibit an oncocytic appearance similar to MTC, making it a potential differential diagnosis.
• Chronic mastitis: In some cases, chronic mastitis can mimic the histological features of medullary carcinoma, particularly in terms of syncytial aggregates.
• Intramammary lymph node: This condition can also display large atypical tumor cells, which may be mistaken for MTC.
• Lymphoma: While lymphoma typically lacks syncytial aggregates, it's essential to consider this diagnosis when evaluating medullary carcinoma.

Other Conditions

• Renal medullary carcinoma: This rare and aggressive cancer can present with occupying renal lesions, making it a potential differential diagnosis for MTC.
• Hypercalcitoninemia: Elevated calcitonin levels can be associated with various conditions, including medullary thyroid carcinoma. However, this condition should not be confused with the differential diagnosis of MTC.

Diagnostic Considerations

When attempting to diagnose medullary carcinoma, it's crucial to consider these potential differential diagnoses and carefully evaluate the histological features, calcitonin levels, and other relevant factors.

• Calcitonin levels: Basal calcitonin values between 10 and 100 pg/mL (determined by IRMA or RIA) should prompt consideration of MTC in the differential diagnosis.
• Histological features: The presence of syncytial aggregates, oncocytic appearance, and other distinctive histological features can help differentiate MTC from other conditions.

References

[4] Cytological diagnosis of MTC on fine-needle biopsy presents some challenges for the pathologist: only 56% of MTCs are accurately diagnosed before surgery (ML Gild, 2023). [9] As seen in Table 2, the differential diagnosis of MTC should be made in cases with basal calcitonin values between 10 and 100 pg/mL (determined by IRMA or RIA) (SPA Toledo, 2009). [14] Other cytological differential diagnosis of MBCs includes chronic mastitis, intramammary lymph node, and lymphoma. Intramammary lymph node and chronic mastitis lack the large atypical tumor cells (AFIP images, Hum Pathol 1989;20:83).