Pseudotumor and lymphoid tumor: distinct clinicopathologic entities

Although in the past some have considered lymphoid tumor to be a form of pseudotumor, clinical, radiologic and pathologic features show them to be distinct entities. Acute pseudotumor presents with abrupt, painful onset, and CT scan shows a diffuse process with no distinct mass to biopsy. Chronic or recurrent pseudotumor leads to a mass of fibrosis apparent on CT scan, which should be biopsied. Lymphoid tumor presents without pain, and orbital CT scan shows a homogenous mass that should be biopsied. Acute pseudotumor usually responds to steroids, but patients with chronic or recurrent pseudotumor may require low-dose radiation or immunosuppressive therapy. Lymphoid tumors that are classified as reactive lymphoid hyperplasia initially may be treated with steroids, followed by low-dose radiation if steroids are ineffective. Orbital lymphomas are treated with higher dose radiation and, perhaps, chemotherapy, if systemic disease is present. Reports of representative cases of acute and chronic pseudotumor and lymphoid tumor illustrate the distinguishing clinical, radiologic and pathologic characteristics of each type of tumor, and recommendations for management of each type are outlined.