What condition is suggested by a slow-growing mandible?

The condition indicated by a slow-growing mandible is hyperpituitarism. This condition occurs due to the overproduction of growth hormone, often caused by a pituitary tumor. As growth hormone levels rise, it leads to increased growth of bones and tissues, including the mandible, resulting in its expansion over time.

In the context of this question, acromegaly, which is also related to excess growth hormone, could lead to similar findings but typically refers to the overall increase in size of extremities and facial features that occurs after epiphyseal closure in adults. Cushing's syndrome involves cortisol excess, which can lead to various systemic effects but doesn't specifically cause slow growth of the mandible. Hypothyroidism results in various metabolic disturbances and might lead to growth retardation in children, but this would not be characterized by a slow-growing mandible in adults.

Thus, hyperpituitarism is the most directly associated with the slow, progressive enlargement of the mandible due to its specific hormonal effects on bone and tissue growth.