A retrospective study of quadrigeminal arachnoid cysts diagnosed by Magnetic Resonance Imaging and Computed Tomography in 26 dogs / Estudo retrospectivo de cistos aracnoides da cisterna quadrigeminal diagnosticados pela ressonância magnética e tomografia computadorizada em 26 cães

Arachnoid cysts are accumulations of cerebrospinal fluid that occur within the arachnoid membrane due to the splitting or duplication of this structure. The aim of this retrospective study is to report the occurrence of this condition in 26 dogs, as well as to describe the findings of computed tomography imaging and magnetic resonance image scans and to correlate these with the clinical signs. A prevalence of the condition was observed in males, predominantly in the small breeds Miniature Pinscher and Shih Tzu, with age raging from 2 months to 9 years. The mainly clinical signs observed in these dogs were seizures and cerebellar ataxia. The study concluded that in 17 dogs the quadrigeminal arachnoid cyst was regarded as an incidental finding, in 6 dogs this condition was regarded as the determinant cause of the clinical signs, and in 3 dogs some clinical signs were associated with arachnoid cyst, but they also presented clinical signs involving others sites of intracranial lesion. (AU)

Cistos aracnoide são acúmulos de líquido cefalorraquidiano que ocorre dentro da membrana aracnoide devido à divisão ou duplicação desta estrutura. O objetivo desse estudo retrospectivo é relatar a ocorrência dessa condição em 26 cães, assim como descrever os aspectos de imagem pela tomografia computadorizada e ressonância magnética e correlacionar com os sinais clínicos. No estudo observamos a prevalência em machos, em raças de pequeno porte, com predomínio de Pinscher miniatura e Shih Tzu, com idade variando de dois meses a nove anos. Os principais sinais neurológicos observados nestes animais foram crises epiléticas e ataxia cerebelar. Foi possível concluir que em 17 cães o cisto aracnoide quadrigeminal foi considerado um achado incidental, em seis cães essa condição foi considerada a causa determinante dos sinais clínicos, e em três cães alguns sinais estavam associados com o cisto aracnoide, porém esses animais apresentaram sinais clínicos relacionados a outros sítios de lesão intracraniana.

[Tectal lipoma: a case report and review of literature]

Intracranial lipomas are rare benign neoplasms that comprise 1% of all primary brain tumors. Generally, occur in midline structure and usually identified incidentally on CT scans or in autopsies. The incidence of intracranial lipomas is about 0.08 to 0.46% on autopsies. These benign lesions are slow-growing, usually asymptomatic and rarely require surgery. We report a 20 years old male who complained of headache since two years ago. On CT examination, a quadrigeminal cistern lipoma without any pressure effect on neural structures demonstrated. His headache remitted with conservative measures. Here, we have a review on the literature and explain CT scan and MRI findings. According to the literature and present case, it seems that direct surgical excision of tumor is not justified in the majority of cases and symptoms of patients greatly respond to conservative measures and, at most, in cases of hydrocephalus, CSF shunting relieves their symptoms

Congenital quadrigeminal lipoma with osteocartilagenous element: A case report

A case of congenital tectal lipoma found incidentally at an autopsy is reported. This female fetus was a product of pregnancy termination at 24 weeks of gestational age after sonographic detection of hydrocephalus. Autopsy revealed a small mass in the periaqueductal portion. The mass was composed of adipose tissue, cartilage, and mature bony tissue with hematopoiesis. The resultant diagnosis was tectal lipoma with osteocartilagenous element. It is uncertain whether the lesion represents a teratoma or hamartoma or mesenchymal metaplasia. The osteocartilagenous component suggests the latter.