[Clinical and pathologic analysis of orbital pseudotumor].

Objective: To investigate the relationship between the histopathology and the imaging analysis of orbital pseudotumor to judge the histopathological types of these tumors before treatment according to imaging analysis, in order to search for different therapeutic approaches for different pathologic types and to predicate prognosis.

Methods: Fifty-six cases (58 eyes) of orbital pseudotumor that had been operated in Tongren hospital were studied. The clinical manifestations of these patients were reviewed. Changes in the imaging analysis and histopathologic examination were observed and their relationship was studied. Methods of treatment and their prognosis were also analyzed.

Results: Historically, the lymphocytic infiltrated type of orbital pseudotumor composed of large amounts of chronic inflammatory cells, only a small amount of collagen was found, so the imaging features of the lymphocytic infiltrated type presented as low or none reflecting areas with a clear posterior demarcation on B scan, and the signals were low or equal on T(1)WI and high on T(2)WI, which could be enhanced by contrast. Oppositely, the fibrotic type was composed of large amounts of fibrotic tissue, and few chronic inflammatory cells were found, so that only the anterior border of the lesion could be identified and the posterior demarcation was blur on the B scan, and the signals were low or equal on T(1)WI and low on T(2)WI, which could not be enhanced or could be enhanced only slightly by changing the contrast. The mixed type presented as an admixture of chronic inflammatory cells and fibric hyperplasia, and the imaging of the mixed type was midway between the lymphocytic infiltrated type and the fibrotic type. Forty-two patients of lymphocytic and mixed types which were identified by histopathology and imaging analysis received a local and systemic corticosteroid therapy. The effect was unstable, and recurrence occurred easily. Therefore, operations were performed on these patients, thirteen of them were treated with low-dose radiotherapy (2 000 - 3 000 cGy) two weeks after operation. Fifteen cases recurred after the operation and 4 cases recurred after the radiotherapy. The fibrotic type of orbital pseudotumor was identified in 12 cases in which no effect could be observed after conservative therapy and operations were performed subsequently. Two cases recurred and were operated again. Exenteration was performed in 2 cases of 56 cases. The cure rate of the composite treatment in the present series was 68.5%.

Conclusions: Different types of orbital pseudotumor present different imaging exhibition, and imaging features are closely related with histopathological changes. Lesions can be localized by CT scan, and also can be localized by B scan and MRI. While it is difficult to obtain a cure result in the orbital pseudotumor, the cure rate can be improved by composite treatment.