Unilateral periorbital pain, cranial nerve palsies and a dramatic response to corticosteroid therapy are the hallmarks of clinical presentation in Tolosa-Hunt-Syndrome (THS) and Idiopathic Pseudotumor of the Orbit (IIPO). Both are unspecific chronic granulomatous diseases of unknown origin, sharing clinical as well as paraclinical characteristics. We observed two patients suffering from acute granulomatous IIPO, who also fulfilled the criteria of THS. Patient 1 developed leftsided infiltration of the medial ocular muscle with periorbital pain and cranial nerve palsy. After an initial response to corticosteroid therapy, contralateral relapse occurred with a THS-like infiltration of the sinus cavernosus and narrowing of the intracavernous internal carotid artery. Granulomatous infiltration of the right sinus cavernosus with secondary involvement of the ipsilateral nervus opticus and a slight exophthalmos was seen in Case 2. According to the literature, MRI and CT show identical signal intensity with different localisation: IIPO preferentially intra- and THS retroorbital. Apart from neuroradiological findings, almost similar histopathology and clinical presentation makes it difficult to distinguish between these two syndromes. Similarities between these two syndromes have been discussed for more than 20 years. Our two cases show their close relationship and we suggest that both diseases belong to the same pathological process.