Evidence for an osteoblast-activating factor in a patient with peripheral T-cell lymphoma and osteosclerosis

Primary hepatic peripheral T-cell lymphoma associated with Epstein-Barr viral infection

Primary hepatic peripheral T-cell lymphoma (H-PTCL) is one of the rarest forms of non-Hodgkin lymphoma. We report a patient who presented with worsening jaundice, abdominal pain, and vomiting. Laboratory values were significant for elevated total bilirubin, alkaline phosphatase, and liver aminotransferases. Following a liver biopsy, histopathology revealed several large dense clusters of atypical T-lymphocytes which were CD2+, CD3+, CD5+, CD7-, CD4+, CD8-, CD56-, CD57-, CD30+ by immunohistochemistry. The proliferation index was approximately 70% by labeling for ki67/mib1. The above histological profile was consistent with peripheral T-cell lymphoma of the liver. Epstein-Barr viral serology indicated a remote infection, a likely risk factor for PTCL. Bone marrow biopsy was negative for malignancy, further supporting hepatic origin.

Vertebral Polyostotic Lymphoma in a Young Dog

An unusual clinical presentation of lymphoma with vertebral involvement in a dog is reported. A 20-month-old intact female Golden Retriever presented with progressive paraparesis and anorexia. Complete blood count and serum biochemistry profile demonstrated pancytopenia and hypercalcemia. Ventral fusion of the lumbar vertebrae by new bony tissue deposition was evident on X-ray and CT scan. Fine needle aspiration revealed neoplastic lymphoid cells in lymph nodes and bone marrow. Histologically, vertebral bone and osteophytes, liver, bone marrow, kidney, and lymph nodes were diffusely infiltrated by neoplastic, lymphoid cells, with scant cytoplasm and round hyperchromatic nuclei. Polyostotic and medullary T-cell lymphoma with spondylosis was diagnosed. Lymphoma mainly affecting bone is uncommon in the dog. The present case differs from previously described polyostotic lymphomas in clinical signs of the disease, mainly attributable to spondylarthrosis. In addition, lymphomatous proliferation was associated with osteoproductive lesions of the vertebrae.

Retroviruses and bone diseases

In 1980, retroviruses were shown to be pathogenic to humans, and experimentation on animals involving retroviruses as causal agents of tumors and degenerative diseases of bone, brain, and lung gained interest. Osteopetrosis, which can be either inherited in rodents or retrovirally induced in cats, is exemplary. Because of replication cycle, retroviruses can be propagated not only as infectious agents but also as cellular genes. If a retroviral infection occurs in germ line cells, the viral genes, which must integrate in the host's DNA, can be passed on to the progeny and inherited as Mendelian characteristics. Therefore, a retroviral etiology could account for diseases that present either as sporadic (infectious) or familial (inherited), although they may be similar in their clinical manifestations. This approach led to the finding of 2 new human retroviruses: 1 in a patient who had sporadic benign osteopetrosis, and the other in a patient who had sporadic paraarticular osteoma. In both patients, the retrovirus was isolated from mononuclear blood cells, not from bone cells, because of the links between bone and the immune system. A systematic search for retroviruses in patients who have sporadic bone disease, which also may appear as inherited disease, has yet to be performed. Patients with sporadic disease could be managed by antiretroviral agents such as Zidovudin.