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.

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.

La sarcoidosis subcutánea o enfermedad de Darier-Roussy es una variante muy poco frecuente de esta enfermedad. No se conoce bien su etiología, aunque se han descrito algunos casos en pacientes con infección crónica por virus de la hepatitis C (VHC), especialmente tras recibir tratamiento con interferón. Presentamos el caso de una paciente con infección por VHC que desarrolló una sarcoidosis subcutánea pocos meses después de recibir tratamiento con interferón, rivabirina y boceprevir. A pesar de que podría tratarse de una asociación casual, convendría estudiar el posible papel del VHC y del tratamiento con interferón en la etiopatogenia de esta enfermedad