Background: Malignant pleural effusions are a serious complication of many late stage cancers that adversely affect quality of life. Pleurodesis with talc slurry is a standard treatment option, but clinical failures occur, possible due to poor talc delivery. A novel drug-delivery system was developed that fills the entire thoracic cavity with a liquid foam containing talc. The foam is designed to gel and adhere to the tissue walls at body temperature, to improve talc deposition and efficacy. Methods: Rheology, foam stability, and ex-vivo coating and bio-adhesion studies were performed on three concentrations of a novel hydrogel talc foam system that was developed to improve delivery of talc to the pleural surfaces. A New Zealand rabbit model of pleurodesis was used to evaluate effectiveness of the foams at inducing adhesion formation and compared to talc slurry. The rabbits were recovered after they had one of the test agents instilled into their pleura, and then sacrificed after 28 days. Pleurodesis was assessed by a blinded pathologist using a standardized pathological scoring system. Results: All talc foam formulations produced foams that gelled at physiological temperatures and were relatively stable for at least two hours. As the concentration of the formulation increased the gelation temperature decreased and the foam adhesiveness increased. Rabbits that received talc foam had significantly greater adhesion formation than talc slurry (mean score of 2.21 vs. 1.18 (p < 0.05)). Rabbits that received the 20% foam developed the most adhesions.Conclusions: This study demonstrates that our triblock copolymer hydrogel foam delivery system enhances adhesion formation in an experimental model. This novel approach can have important clinical impact, potentially improving efficacy of existing therapies and reducing the need for more invasive treatments.

Background Malignant pleural effusion (MPE) is a devastating sequela associated with cancer. Talc pleurodesis is a common treatment strategy for MPE but has been estimated to be unsuccessful in up to 20–50% of patients. Clinical failure of talc pleurodesis is thought to be due to poor dispersion. This monograph reports the development of a foam delivery system designed to more effectively coat the pleural cavity. Methods C57BL/6 mice were injected with Lewis lung carcinoma (LL/2) cells intrapleurally to induce MPE. The mice then received either normal saline (NS) control, foam control (F), talc slurry (TS, 2 mg/g) or talc foam (TF, 2 mg/g). Airspace volume was evaluated by CT, lungs/pleura were collected, and percent fibrosis was determined. Results The TF group had significantly better survival than the TS group (21 vs 13.5 days, p < 0.0001). The average effusion volume was less in the talc groups compared to the control group (140 vs 628 μL, p < 0.001). TF induced significant lung fibrosis ( p < 0.01), similar to TS. On CT, TF significantly ( p < 0.05) reduced loss of right lung volume (by 30–40%) compared to the control group. This was not seen with TS ( p > 0.05). Conclusions This report describes using a novel talc foam delivery system for the treatment of MPE. In the LL/2 model, mice treated with the TF had better survival outcomes and less reduction of lung volume than mice treated with the standard of care TS. These data provide support for translational efforts to move talc foam from animal models into clinical trials.

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Background Histiocytic sarcoma is a rare neoplasm of mature histiocytes with a wide range of clinical presentations and manifestations. The heterogeneity of this neoplasm can cause difficulty in both diagnosis and treatment. It is a diagnosis of exclusion, requiring verification of the histiocytic lineage and the exclusion of other B-cell related malignancies. Although cases of postrenal transplant histiocytic sarcoma have been reported, incidences in a native kidney are rare. Case Report We present the case of a 70-year-old male with a history of colorectal adenocarcinoma, status post chemotherapy, with an incidental exophytic renal mass found on imaging, which was determined to be a sarcomatoid renal cell cancer on biopsy. Radical nephrectomy was performed, revealing a 4.5 × 3.5 × 3.2-cm mass invading the renal pelvis and fat. Microscopic examination of the tumor showed large, poorly cohesive neoplastic cells with abundant pale, eosinophilic cytoplasm that stained positive for vimentin, CD4, CD163, and CD68 and weakly/focally positive for lysozyme. Negative immunostains included PAX-8, pan-CK, AE1/AE3, HMB45, S100, CD34, CD30, ALK1, CD1a, myeloperoxidase, CD138, myo-D1, SMA, and CD21. A diagnosis of histiocytic sarcoma, grade 4 was made based on these findings. Discussion Histiocytic sarcoma is a disease of unknown etiology accounting for less than 1% of all hematolymphoid neoplasms. Our literature review revealed no other cases arising de novo in the kidney, but several cases were reported in postrenal transplant patients. Diagnosis of histiocytic sarcoma is difficult as it is a diagnosis of exclusion. The immunohistochemical profile most often expresses lysosome-related markers, such as CD68, CD163, or lysozyme. Additionally, negative staining is expected for markers related to B cells, T cells, and melanocytes. The cells are often large with eosinophilic cytoplasm, well-defined borders, and vesicular chromatin. Although there are numerous differentials, distinct morphologic and immunohistochemical features allow for accurate diagnosis.