Effects of Systemic or Local Administration of Mesenchymal Stem Cells from Patients with Osteoporosis or Osteoarthritis on Femoral Fracture Healing in a Mouse Model.

The purpose of this study was to analyze the regenerative capacity of mesenchymal stem cells (MSCs) in the treatment of fractures. MSCs extracted from patients with osteoporotic hip fractures or hip osteoarthritis undergoing hip replacement surgeries were cultured and injected into mice with femoral fracture. Two experimental models were established, one for the systemic administration of MSCs (n = 29) and another one for local administration (n = 30). Fracture consolidation was assessed by micro-CT and histology. The degree of radiological consolidation and corticalization was better with MSCs from osteoporosis than from osteoarthritis, being significant after systemic administration (p = 0.0302 consolidation; p = 0.0243 corticalization). The histological degree of consolidation was also better with MSCs from osteoporosis than from osteoarthritis. Differences in histological scores after systemic infusion were as follows: Allen, p = 0.0278; Huo, p = 0.3471; and Bone Bridge, p = 0.0935. After local administration at the fracture site, differences in histological scores were as follows: Allen, p = 0.0764; Huo, p = 0.0256; and Bone Bridge, p = 0.0012. As osteoporosis and control groups were similar, those differences depended on an inhibitory influence by MSCs from patients with osteoarthritis. In conclusion, we found an unexpected impairment of consolidation induced by MSCs from patients with osteoarthritis. However, MSCs from patients with osteoporosis compared favorably with cells from patients with osteoarthritis. In other words, based on this study and previous studies, MSCs from patients with osteoporosis do not appear to have worse bone-regenerating capabilities than MSCs from non-osteoporotic individuals of similar age.

Low-fat, plexiform spindle cell lipoma of the lip expressing S100 protein: a neural tumor simulator.

The plexiform variant of spindle cell lipoma is very uncommon. In fact, as far as we are aware only seven cases have been previously reported. We describe herein the case of a 49-year-old man with a smooth nodule of the mucosa of the lower lip that was gradually increasing. Surgical excision of the lesion was done and the study revealed the histological and immunohistochemical features of a plexiform spindle cell lipoma (PSCL). Peculiar to this case was the location in the lip, the presence of abundant S100-positive dendritic cells, and scarce mature lipogenic cells. S100 protein reactivity has rarely been observed in classical and plexiform spindle cell lipoma. To our knowledge, no case of PSCL displaying abundant S100-positive dendritic cells has been described. This feature may lead to a diagnostic pitfall. The main differential diagnosis includes the neuroma group, plexiform intraneural neurofibroma (PIN), plexiform schwannoma and plexiform hybrid tumor of perineurioma and cellular neurothekeoma. It is imperative correctly diagnose and differentiate PSCL from neural tumors because they may show syndromic associations, have different prognosis, including malignant transformation in PIN, and the management of all these lesions differs.

AA Amylodisis Associated with Jugular Paraganglioma as a Rare Cause of Chronic Diarrhea.

We report a case of a 64-year-old man with chronic diarrhea who was diagnosed of a systemic reactive (AA) amyloidosis associated with a jugular paraganglioma. This neoplasm was diagnosed 30 years previously and it was not removed after extensive evaluation by a multidisciplinary team. Chronic inflammatory diseases are the major cause of AA amyloidosis. However, benign tumors, such as jugular paragangliomas, are considered to be one of the tumors that can result in AA amyloidosis.