Renal cell carcinoma metastasizing to solitary fibrous tumor of the pleura: a case report

<p>Abstract</p> <p>Introduction</p> <p>A tumor metastasizing to another malignancy is an uncommon phenomenon. Since it was first described in 1902, there have been fewer than 200 cases reported in the literature, with lung cancer metastasizing to renal cell carcinoma being the most frequently described pattern. Here we report a case of a solitary fibrous tumor of the lung acting as the recipient for a renal cell carcinoma. To our knowledge, this is the first reported case of such a combination and the second case involving a solitary fibrous tumor.</p> <p>Case presentation</p> <p>A 58-year-old Caucasian man who developed a persistent dry cough presented to our hospital. Imaging studies revealed a large pleural-based mass in the left lung. A biopsy of the mass showed a spindle-cell lesion consistent with a solitary fibrous tumor. The patient underwent surgical excision of the 13 cm mass. The pathological examination confirmed the diagnosis of a solitary fibrous tumor but also demonstrated discrete foci of metastatic renal cell carcinoma. Until that point, a primary renal cell carcinoma tissue diagnosis had not been made and the initial radiological work-up was inconclusive.</p> <p>Conclusion</p> <p>Awareness of the unusual phenomenon of tumor-to-tumor metastasis is important for practicing surgical pathologists, particularly in the evaluation of a mass lesion showing bimodal histology. This case also highlights the importance of careful examination of surgical specimens, as minute and unusual findings can direct patient care.</p

Development of Circadian Oscillators in Neurosphere Cultures during Adult Neurogenesis

Circadian rhythms are common in many cell types but are reported to be lacking in embryonic stem cells. Recent studies have described possible interactions between the molecular mechanism of circadian clocks and the signaling pathways that regulate stem cell differentiation. Circadian rhythms have not been examined well in neural stem cells and progenitor cells that produce new neurons and glial cells during adult neurogenesis. To evaluate circadian timing abilities of cells undergoing neural differentiation, neurospheres were prepared from the mouse subventricular zone (SVZ), a rich source of adult neural stem cells. Circadian rhythms in mPer1 gene expression were recorded in individual spheres, and cell types were characterized by confocal immunofluorescence microscopy at early and late developmental stages in vitro. Circadian rhythms were observed in neurospheres induced to differentiate into neurons or glia, and rhythms emerged within 3-4 days as differentiation proceeded, suggesting that the neural stem cell state suppresses the functioning of the circadian clock. Evidence was also provided that neural stem progenitor cells derived from the SVZ of adult mice are self-sufficient clock cells capable of producing a circadian rhythm without input from known circadian pacemakers of the organism. Expression of mPer1 occurred in high frequency oscillations before circadian rhythms were detected, which may represent a role for this circadian clock gene in the fast cycling of gene expression responsible for early cell differentiation