Inappropriate thyrotropin secretion is a rare laboratory finding that may be related to multiple differential diagnosis. The presence of a pituitary adenoma usually relates to a thyroid-stimulating hormone (TSH) producing adenoma; however, the possibility of incidentalomas and other tumors should be considered. Differential diagnosis requires careful clinical evaluation and family history evaluation, especially when the most complicated tests are unavailable. We present two cases, one with a TSH producing adenoma and other with a non-functioning pituitary adenoma and thyroid hormone resistance that was diagnosed using the available clinical data, showing that not all the tests are necessary to provide adequate treatment if the clinical tools are considered.