Malignant thymoma in a patient with HIV positivity: a case report with a review of the differential cytologic diagnoses

Type B thymoma in a patient with HIV infection: A case report with a review of HIV and thymoma coexistence

HIV infection predisposes people to cancer, including AIDS‐defining cancers, such as Kaposi sarcoma, and a broad range of non‐AIDS‐defining cancers. Here we report a case with rare coexistence of HIV and thymoma, and summarize all the comorbid cases that currently exist. We found that in all the cases reported, thymoma occurred when CD4+ counts were within a normal range, but the immune response in peripheral T‐cell repertoire remains unknown. In our case, an overview of the immune system under this complicated situation is given for the first time by showing the lymphocyte subpopulations in the blood and the immune cell distribution of the thymoma. This case expands the scope of non‐AIDS‐defining cancers, and provides insight into the influence of the immune system under two immunocompromising conditions, HIV infection and thymoma.

Thymic carcinoma in a child with HIV infection

HIV infection predisposes to cancer during childhood. In addition to the AIDS-defining non-Hodgkin lymphoma (NHL) and Kaposi sarcoma, a range of other lymphoid malignancies and solid tumors have been described. We report the first case of an HIV-positive child with thymic carcinoma in the setting of regressing thymic cysts. The tumor expressed CKIT but failed to respond to imatinab mesylate after a transient response to multiagent chemotherapy. This case extends the spectrum of pediatric malignancy in the setting of HIV and suggests that patients with presumed benign thymic cysts require ongoing surveillance.

Severe T- and B-cell immune deficiency associated with malignant thymoma

BACKGROUND

Immunodeficiency with thymoma syndrome is a rare disorder that generally occurs after the fourth decade of life. Typically, thymic tumors are benign, and gradually developing immunodeficiency consists of hypogammaglobulinemia with low B-cell counts and an inverted CD4+/CD8+ T-cell ratio due to excessive CD8+ T cells.

OBJECTIVE

To report the case of a 32-year-old, white man with an invasive malignant thymoma and profound combined T- and B-cell immunodeficiency associated with a normal CD4+/CD8+ T-cell ratio, absence of circulating B cells, and infection with an unusual organism.

METHODS

The patient presented with a superior vena cava syndrome caused by a malignant thymoma. During chemotherapy and radiotherapy, he experienced recurrent episodes of pulmonary infections due to Haemophilus influenza and Serratia marcescens and persistent oral thrush. He was diagnosed as having thymoma and underwent immunological evaluation.

RESULTS

Sixteen months after the diagnosis of thymoma, the immunological evaluation revealed profound lymphopenia, eosinopenia, very low counts of both CD4+ T cells and CD8+ T cells, and a normal CD4+/CD8+ ratio with negative delayed-type hypersensitivity skin test results. Hypogammaglobulinemia and absent specific antibody responses were associated with a lack of peripheral blood CD19+ B cells. Despite treatment with intravenous immunoglobulin, the patient died of respiratory insufficiency and sepsis secondary to a chronic pulmonary infection.

CONCLUSIONS

Malignant thymoma may be associated with severe combined immunodeficiency. A normal CD4+/CD8+ ratio and the absence of peripheral B cells suggest a bone marrow defect that affects both T and B cells in the pathogenesis of this syndrome. Comprehensive immunological evaluation should be performed when thymoma is diagnosed to initiate an early and effective treatment to prevent life-threatening complications.

Rhabdomyosarcoma in a child with massive pleural effusion: cytological diagnosis from pleural fluid

We report on a case of embryonal rhabdomyosarcoma in an 11-yr-old boy investigated for mild chest pain after trauma. Chest radiography showed a massive right pleural effusion. Cytological analysis of the pleural fluid demonstrated the presence of malignant small undifferentiated cells. The rhabdomyoblastic nature of the cells was confirmed by positive immunostains of HHf35 actin, desmin, and skeletal muscle myosin; histological examination of a core biopsy confirmed the diagnosis of rhabdomyosarcoma. Computed tomography and gallium scan revealed the presence of an extensive anterior and lower chest wall mass involving the mediastinum, as well as retroperitoneal lymphadenopathy. Massive pleural effusion is a frequent presentation in malignant disease, but is rare in rhabdomyosarcoma. The immunochemical stain studies performed on cytological smears in this case proved to be very useful for making the definitive and accurate diagnosis. Diagn. Cytopathol. 1999;21:125-128.