A 52-year-old man presents to the outpatient clinic with a 10-year history of progressive coarsening of facial features. His wife notes that he requires larger shoes and gloves every few years. On examination, the structure marked **A** in the diagram—a prominent protruding lower jaw with new dental gaps—is evident. He also reports excessive sweating, new-onset joint pain, and recent diagnosis of type 2 diabetes. Which of the following is the most likely diagnosis?

Explanation

## Why Acromegaly with growth hormone-secreting pituitary adenoma is right Prognathism (protruding lower jaw) marked as **A** is a hallmark facial feature of acromegaly, caused by excessive growth hormone secretion from a pituitary adenoma. The clinical presentation is classic: progressive coarsening of features over years, increased shoe/glove sizes (soft tissue hypertrophy), new interdental spacing and dental malocclusion (due to mandibular overgrowth), excessive sweating, arthralgias, and type 2 diabetes. Harrison 21e Ch 380 emphasizes that prognathism with malocclusion and new dental gaps is a cardinal sign of acromegaly, often prompting patients to seek dental care before endocrine evaluation. The 10-year insidious onset with sequential worsening is typical, as diagnostic delay of 5–10 years is common. ## Why each distractor is wrong - **Hypothyroidism with myxedema and facial coarsening**: While myxedema can cause facial puffiness and coarsening, it does NOT produce prognathism, progressive mandibular overgrowth, or new interdental spacing. Myxedema is characterized by non-pitting edema and loss of facial definition, not jaw protrusion. The history of increasing shoe/glove sizes and new-onset diabetes are incompatible with hypothyroidism. - **Paget's disease of bone with secondary hyperparathyroidism**: Paget's disease causes bone deformity and can enlarge the skull, but it does NOT produce the characteristic prognathism with soft tissue overgrowth, macroglossia, or the systemic features (sweating, arthralgias, diabetes) seen in acromegaly. Paget's is primarily a skeletal disorder, not an endocrine syndrome. - **Cushing's syndrome with glucocorticoid-induced facial changes**: Cushing's syndrome causes moon facies, plethora, and hirsutism, but NOT prognathism or progressive mandibular overgrowth. The history of increasing shoe/glove sizes is incompatible with Cushing's. Cushing's typically presents with proximal weakness, hypertension, and hyperglycemia, but not the progressive soft tissue hypertrophy characteristic of acromegaly. **High-Yield:** Prognathism + new interdental spacing + progressive increase in shoe/glove sizes over years = acromegaly until proven otherwise; sequential photo comparison is often diagnostic. [cite: Harrison 21e Ch 380; Acromegaly clinical features and diagnosis]