What post-ganglionic lesion typically does NOT present with anhidrosis in Horner's syndrome?

In Horner's syndrome, a classic triad of symptoms occurs: ptosis (drooping of the eyelid), miosis (constricted pupil), and anhidrosis (lack of sweating) on the affected side of the face. The syndrome results from disruption of the sympathetic nerve pathways that innervate these structures.

Carotid artery dissection is a condition where there is a tear in the carotid artery wall, and it can affect sympathetic fibers traveling alongside the artery. However, it does not typically result in anhidrosis because the sympathetic fibers responsible for sweating are not primarily affected in this condition. Instead, the predominant symptoms are related to ocular effects, such as ptosis and miosis.

In contrast, other conditions mentioned, like syringomyelia, Pancoast's tumor, and multiple sclerosis, have more systemic involvement that can affect the sympathetic pathways leading to symptoms including anhidrosis. Syringomyelia can damage the sympathetic fibers as they traverse the spinal cord, leading to the complete manifestation of Horner's syndrome including anhidrosis. Pancoast's tumor can impinge upon the sympathetic chain in the upper thoracic region, again leading to the full triad of symptoms. Multiple sclerosis, due to its involvement