Bone marrow (BM) fibrosis could occur secondarily to several clinical disorders: hematological and nonhematological. Clinical presentation of fibrosis could occur in myeloproliferative diseases, lymphoma, myelodysplastic syndrome and myeloma. The pathophysiology underlying BM fibrosis remains unclear despite intensive study, with a corresponding lack of specific therapy. This review discusses new insights in the role of substance P, cytokines and fibronectin in the development of BM fibrosis. Substance P is a neuropeptide that possesses pleiotropic properties, e.g. neurotransmission and immune/hematopoietic modulation and is linked to BM fibrosis. Cytokines and growth factors, in particular those associated with fibrogenic properties, e.g. TGF-β, IL-1 and platelet-derived growth factor, are linked to BM fibrosis. Extracellular matrix proteins are increased in patients with BM fibrosis. Fibronectin in the sera of patients with BM fibrosis is complexed to substance P. Fibronectin appears to protect substance P from degradation by endogenous peptidases. This review describes the preliminary findings on the colocalization of substance P and fibronectin in the BM of patients with fibrosis. These data are reviewed in the context of published reports with particular focus on the relevant cytokines. A more detailed understanding of intra- and intercellular mechanisms in BM fibrosis may lead to effective therapy.

We report a case of plasmacytoma of the testis without evidence of bone or immunoglobulin abnormalities. The presentation, evaluation and management of this extremely unusual tumor are reviewed.

Substance P (SP), also considered a proinflammatory cytokine, as well as others such as transforming growth factor-β1 (TGF-β1) and interleukin-1 (IL-1), and the extracellular matrix protein fibronectin (FN) have been associated with the pathophysiology of myelofibrosis. SP is encoded by the TAC1 gene. The relationships among SP, TGF-β1, IL-1 and FN are poorly understood. This study determined the mechanisms for concomitant production of IL-1, TGF-β1 and SP and also determined the synergistic role of FN in SP release. Enzyme-linked immunosorbent assay (ELISA) indicated increased levels of SP and TGF-β1 in the blood of patients with myelofibrosis. Monocytes, shown to be activated in patients with bone marrow (BM) fibrosis, expressed the TAC1 gene for SP release, in a nuclear factor-κB (NFκB)-dependent manner. Reporter gene assay with the 5' regulatory region of TAC1 indicated its expression by high levels of FN and TGF-β1. Immunohistochemical studies of paraffin-embedded BM biopsies from patients with myelofibrosis, and age-matched controls without fibrosis, indicated co-localization of SP and its receptor neurokinin-1 (NK1). In summary, myelofibrotic monocytes have autocrine loops that stimulate the release of SP and TGF-β1, and that are potentiated by fibronectin. The FN-mediated induction of SP in turn stimulates monocytes through autostimulation by NK1 receptors. These findings, combined with those of previous studies, demonstrate an adhesion-mediated NFκB/IL-1/TGF-β1 axis that can be initiated by increased FN in patients with myelofibrosis for the production of SP. These findings show how TGF-β1 and SP production are coupled, and suggest new therapeutic targets to reverse immune-mediated fibrosis.

A patient with carcinoid tumor of the head of pancreas and carcinoid syndrome presented without liver metastasis. The patient had retroperitoneal lymphadenopathy. He had symptoms of flushing, diarrhea and abdominal pain. 5-Hydroxyindoleacetic acid (5-HIAA) was elevated. Absence of liver metastasis was documented not only by the negative computed tomography (CT) scan and liver/spleen scan, but also by autopsy. Except for carcinoid arising from ovary, testis, or bronchi, the other carcinoid tumors rarely cause carcinoid syndrome without liver metastasis. The literature was reviewed, and the findings are presented.

We report the neuropathologic findings in the first patient with recognized glutamate dehydrogenase (GDH) deficiency to come to postmortem examination. He had progressive cerebellar ataxia beginning at age 21. He died at age 47 of pulmonary emboli. Postmortem examination revealed pancerebellar, olivary, and mild pontine atrophy, demyelination of the posterior columns, degeneration of anterior horn and dorsal root ganglion cells, and reduction of myelinated fibers in the sural nerve. In addition, there was neuronal storage of lipopigment diffusely throughout the CNS and the autonomic neurons, with cell distention, atrophy, and loss in selected areas.