Rathke cleft cysts are associated with a variety of clinical presentations and sometimes confusing intraoperative and pathological findings. Close postoperative observation with neuroimaging and neuroophthalmological assessment is necessary, especially after a partial removal, as in cases with squamous metaplasia.

The 2000 WHO classification has identified the truly aggressive meningiomas better than did the previous criteria. A precise meningioma grading system may help to avoid over-treatment of patients with an atypical meningioma as, once the tumour has "declared itself" by recurrence and histological features, it becomes a tumour that is poorly amenable to current therapies.

We studied the distributions of interneurons containing the calcium‐binding proteins parvalbumin and calbindin D‐28k, as well as that of pyramidal neurons containing nonphosphorylated neurofilament (NNF), in the middle temporal visual area (MT) of marmoset monkeys. The distributions of these classes of cells in MT are distinct from those found in adjacent areas. Similar to the primary visual area (V1), in MT, calbindin‐immunopositive neurons can be objectively classified into “dark” and “light” subtypes based on optical density of stained cell bodies. Calbindin‐positive dark neurons are particularly concentrated in layers 2 and 3, whereas light neurons have a more widespread distribution. In addition, a subcategory of calbindin‐positive dark neuron, characterized by a “halo” of stained processes surrounding the cell body, is found within and around layer 4 of MT and V1. These cells are rare in most other visual areas. In comparison, parvalbumin‐immunopositive cells in area MT have a relatively homogeneous distribution, although with a trend toward higher spatial density in lower layer 3, and are relatively uniform in terms of density of staining. Finally, MT shows a characteristic trilaminar distribution of NNF‐immunopositive pyramidal cells, with stained cell bodies evident in layers 3, 5, and 6. Although the laminar distribution of cells stained for the three markers overlap to some extent, these subcategories can be readily distinguished in terms of morphology, including cell body size. Chemoarchitectural parallels observed between MT and V1 suggest comparable physiological requirements and neuronal circuitry. J. Comp. Neurol. 500:832–849, 2007. © 2006 Wiley‐Liss, Inc.

Subtotal resection with or without radiation or radiosurgery should be considered as a suitable treatment option for patients with petroclival meningiomas, especially the elderly, because the growth rate of residual tumors is low.