Pituitary pars intermedia dysfunction in horses associated to pituitary adenoma

Abstract

The clinical syndrome of the pituitary pars intermedia dysfunction (PPID) is the most common endocrinopathy of older horses. This syndrome is characterized by several clinical and pathological changes, which are usually associated with adenomas of the pars intermedia (PI) of the pituitary gland. The aim of this work is to describe five cases of pituitary adenoma of the PI associated with PPID in horses, addressing its clinical and pathological aspects. The horses had a mean of 22 years of age. The main clinical signs were hirsutism and paresis of hind limbs, and at post mortem examination all horses had hirsutism, and a nodule in the pituitary gland, which was histologically characterized as an adenoma of PI (5/5). Furthermore, two horses had gross lesions suggestive of chronic laminitis. Moreover, there was intense parasitism of Sarcocystis neurona (2/5), Strongylus vulgaris (1/5), Parascaris equorum (1/5), Draschia megastoma (1/5), and Klossiella equi (1/5).

A síndrome clínica da disfunção da pars intermedia da hipófise (PPID) é a endocrinopatia mais comum em cavalos idosos. Essa síndrome é caracterizada por várias alterações clínicas e patológicas, geralmente associadas a adenomas da pars intermedia (PI) da hipófise. O objetivo deste trabalho é descrever cinco casos de adenoma hipofisário de PI associado a PPID em equinos, abordando seus aspectos clínicos e patológicos. Os cavalos apresentaram média de 22 anos de idade. Os principais sinais clínicos incluíam hirsutismo e paresia dos membros pélvicos, e no exame post mortem todos os equinos apresentavam hirsutismo e um nódulo na glândula pituitária, que foi histologicamente caracterizada como um adenoma de PI (5/5). Além disso, dois cavalos tinham lesões macroscópicas sugestivas de laminite crônica. Ainda, havia intenso parasitismo de Sarcocystis neurona (2/5), Strongylus vulgaris (1/5), Parascaris equorum (1/5), Draschia megastoma (1/5) e Klossiella equi (1/5).