Pseudotumor In Patient Research Articles

Radiation-induced pseudotumor following therapy for soft tissue sarcoma

The purpose of this study was to describe the prevalence and imaging appearance of radiation induced pseudotumors in patients following radiation therapy for extremity soft tissue sarcomas. We retrospectively reviewed the serial magnetic resonance (MR) images of 24 patients following radiation therapy for extremity soft tissue sarcomas. A total of 208 exams were reviewed (mean, 8.7 exams per patient) and included all available studies following the start of radiation therapy. Exams were analyzed for the identification of focal signal abnormalities within the surgical bed suggesting local tumor recurrence. Histopathologic correlation was available in nine patients suspected of having local tumor recurrence. Additional information recorded included patient demographics, tumor type and location, radiation type, and dose. The study group consisted of 12 men and 12 women, having an average age of 63 years (range, 39-88 years). Primary tumors were malignant fibrous histiocytoma (n = 13), leiomyosarcoma (n = 6), liposarcoma (n = 3), synovial sarcoma (n = 1), and extraskeletal chondrosarcoma (n = 1). All lesions were high-grade sarcomas, except for two myxoid liposarcomas. Average patient radiation dose was 5,658 cGy (range, 4,500-8,040 cGy). Average follow-up time was 63 months (range, 3-204 months). Focal signal abnormalities suggesting local recurrence were seen in nine (38%) patients. Three of the nine patients with these signal abnormalities were surgically proven to have radiation-induced pseudotumor. The pseudotumors developed between 11 and 61 months following the initiation of radiation therapy (mean, 38 months), with an average radiation dose of 5,527 cGy (range, 5,040-6,500 cGy). MR imaging demonstrated a relatively ill-defined ovoid focus of abnormal signal and intense heterogeneous enhancement with little or no associated mass effect. MR imaging of radiation-induced pseudotumor typically demonstrates a relatively ill-defined ovoid mass-like focus of intense heterogeneous enhancement with little or no associated mass effect. Imaging follow-up or biopsy may be an alternative course of action to surgical re-exploration if this diagnosis is considered. The study revealed radiation-induced pseudotumor in 12.5% of patients in our extremity study group, suggesting that radiation-induced pseudotumor may be more prevalent than previously reported.

Significance of Inflammatory Pseudotumors in Patients with a History of Bladder Cancer

To study the significance of inflammatory pseudotumor (IPT) in patients with a history of bladder cancer. We surveyed our hospital database for patients who developed IPT during follow-up of bladder cancer. The original histologic blocks were reviewed and immunostained for vimentin, anaplastic large cell lymphoma (ALK), and pancytokeratin. Between the years 1988 and 2005, a total of 809 patients were registered in the database, and 16 patients (2%) developed IPT during follow-up. All patients had initial high-grade tumor. Immunostaining for vimentin was positive in all patients, ALK was negative in all patients, and pancytokeratin positive in only 2 patients. During follow-up, 12 patients (75%) developed tumor recurrence, 9 patients (56%) tumor progression, and 6 patients (37.5%) died of bladder cancer. Median period from the finding of IPT to tumor recurrence was 16 months, to progression 7 months, and to mortality 26 months. The finding of IPT in a patient with a history of bladder cancer is associated with a high risk of tumor recurrence, progression, and cancer-related mortality. Second- and possibly third-look bladder biopsies should be considered. The unique characteristics of IPT in patients with a history of bladder cancer suggest that this is a separate disease entity.

Spindle Cell Pseudotumor due to Mycobacterium avium-intracellulare in Patients With Acquired Immunodeficiency Syndrome (AIDS)

A rare spindle-cell pseudotumor caused by Mycobacterium avium-intracellulare (MAI) that mimics a mesenchymal tumor, was recently reported (7,14). We report on three such pseudotumors in patients with the acquired immunodeficiency syndrome (AIDS), two involving lymph nodes and one involving the bone marrow. In the course of investigating the first-encountered example of this tumor for evidence of smooth-muscle origin of the spindle cells, it was noted that these cells stained positively for desmin by immunoperoxidase techniques (IPX), as did a variety of other cytoskeleton filaments of all sizes. Electron microscopic examination of one of these lesions revealed spindle cells containing lysosomes and large numbers of microorganisms compatible with MAI but no filaments or organelles suggestive of smooth-muscle cells. Further studies revealed that the typical lesions produced by MAI in patients with AIDS, namely aggregates of histiocytes or individual histiocytes laden with organisms, rather than the expansile spindle-cell pseudotumor, also strain strongly for cytoskeleton filaments, as do M. tuberculosis and Mycobacterium leprae. Awareness of the existence of this unusual manifestation of MAI infection in AIDS patients and its desmin positivity can avoid misdiagnosis of a primary or metastatic smooth-muscle neoplasm. The cell of origin appears to be the histiocyte.