BACKGROUND: Pineal apoplexy (either hemorrhagic or ischemic) may complicate the course of a tumor at this site. This event usually is characterized by an acute clinical onset and requires emergency surgical management whereas the regression of the lesion is a much rarer outcome.
METHODS: Three cases of pineal vanishing tumors in the pediatric population are reported and the pertinent literature is reviewed.
RESULTS: In one case, radiologic findings were consistent with a diagnosis of pineal cyst, which became symptomatic after a spontaneous hemorrhage. This event may also explain its regression after the treatment of associated hydrocephalus. In the remaining 2 cases, neuroimaging examinations disclosed a solid tumor. One of them regressed after a surgical biopsy, probably because of an ischemic evolution, whereas the last one disappeared without any medical or surgical manipulation. Neither hemorrhage nor ischemia were noticed, thus the mechanism of regression remains controversial.
CONCLUSIONS: Vanishing tumors of the pineal region may occur in different circumstances, resulting from absence of any medical and surgical action to minor manipulation of the tumor to obtain a biopsy. This variety may reflect different underlying mechanisms, leading to hemorrhagic or ischemic change of the tumor and its subsequent regression, although radiological imaging may fail to document hemorrhage or ischemia.

BACKGROUND: A ghost tumor (GhT) is a space-occupying lesion with radiologic features consistent with the diagnosis of tumor that on further investigation is revealed not to be a tumor, although definitions in the literature are inconsistent, and the incidence of GhT remains undefined.
METHODS: A review of the pertinent literature was performed to identify pediatric patients in whom a misleading initial diagnosis of space-occupying lesion was described. Analysis of the differentiating features of the final diagnosis and related clinical and radiologic issues was performed.
RESULTS: GhT may be categorized as follows: GhT I, lesions spontaneously disappearing during follow-up, also known as \"vanishing tumors\"; GhT II, nonneoplastic space-occupying lesions showing a tumor appearance, also known as \"tumor-like lesions\"; GhT III, anatomic variants of normal structures mimicking a tumor, also defined as \"false tumors.\" The most deceptive conditions and critical points in the differential diagnosis of these cases were discussed.
CONCLUSIONS: GhT is an entity with significant implications in regard to treatment and outcome. In this context, the integration of clinical and radiologic clues is crucial for a careful differential diagnosis and a consistent diagnostic approach, which is necessary for adequate decision making regarding management. A thorough radiologic work-up is mandatory. Atypical radiologic images should raise a high level of suspicion, including incidental lesions, which are encountered with increasing frequency in daily practice as a result of greater access to radiologic examinations, increasing sensitivity of imaging, and the impact of defensive medicine. A wait-and-see policy should be considered whenever indicated.