Treatment of metastatic squamous cell carcinoma arising in sacrococcygeal pilonidal sinus: a case report series.

Background: Squamous cell carcinoma (SCC) arising in a sacrococcygeal pilonidal sinus is rare, with cases of metastatic disease being even rarer. Among published cases, almost none have reported on systemic treatment. Objective: This disease has a poorer prognosis than other forms of cutaneous SCC; therefore, our objective is to shed some light on the treatment of metastatic disease. Methods: We present a series of nine cases treated at a single center, four of whom received systemic treatment. Additionally, other previously reported cases of metastatic disease are included in an attempt to draw stronger conclusions. Results: Four patients were treated under several treatment regimens, with a median progression-free survival of only 2 months and two instances of partial response (18%). The best result was achieved with cemiplimab. Across all the cases, there was a trend toward a benefit of the use of systemic treatment (HR 0.41, 95% CI 0.15-1.12, p = 0.083; median overall survival 13 vs. 8 months). Limitations: Limitations include the significant lack of information on previously published cases and the extremely heterogeneous nature of the existing information. Conclusion: The initial systemic treatment should be an anti-PD-1, as with other SCCs. After progression on anti-PD-1, there is no strong evidence to support the recommendation of a specific treatment or sequence: options include cetuximab and/or chemotherapy (platinum, paclitaxel, 5-fluorouracyl).

Effect of VEGF-A165 addition on the integration of a cortical allograft in a tibial segmental defect in rabbits.

PURPOSE: Long-bone segmental defects caused by infection, fracture, or tumour are a challenge for orthopaedic surgeons. Structural allografts are sometimes used in their treatment but their poor biological characteristics are a liability. The objective of this study was to determine whether the addition of recombinant vascular endothelial growth factor-A (VEGF) to a structural allograft improved its integration into a rabbit tibial segmental defect in a non-union model. METHODS: Tibial segmental defects were filled with heat sterilized allogenic tubular tibiae sections and then stabilized with a screw plate. In the VEGF treatment group (n = 6 tibiae), 2 µg of VEGF added to a 50 µl matrigel solution was inserted into the allograft cavity. In the control group (n = 6 tibiae), only matrigel was added. After 12 weeks, macroscopic and microscopic analysis, radiographs, and computerized micro-tomography (micro-CT) were performed. If allograft consolidation was present, a torsional resistance analysis was performed. RESULTS: Addition of VEGF to the allograft decreased the rate of osteosynthesis failure compared with the control group (1/6 vs. 5/6, p = 0.08), increased trabecular continuity evaluated by micro-CT in the bone-allograft interphases (8/12 vs. 2/12, p = 0.036) and histological trabecular continuity (7/12 vs. 0/12, p = 0.0046). Full consolidation was observed in three tibiae of the VEGF group and one in the control group (differences not significant); however, torsional resistance showed no significant differences (n.s.). CONCLUSION: Addition of VEGF to a structural allograph inserted into a rabbit tibial segmental defect increased allograft integration rate. Further research in this direction might help clinicians in dealing with large bone defects.

The effect of the addition of adipose-derived mesenchymal stem cells to a meniscal repair in the avascular zone: an experimental study in rabbits.

PURPOSE: To determine whether adipose-derived mesenchymal stem cells (ASCs) affect the healing rate of meniscal lesions sutured in the avascular zone in rabbits. METHODS: Four groups were used. In group A (n = 12) a short, 5-mm-long longitudinal lesion in the avascular zone of the anterior horn of the medial meniscus was created and immediately sutured. In group B (n = 8) the same short lesion was created but suture was delayed 3 weeks. In group C (n = 12) a larger, 15-mm-long lesion that spanned the whole meniscus was created and sutured immediately. In group D (n = 8) the same large lesion was sutured 3 weeks later. Both knees in each rabbit were used: 1 served as the control, and in the other, 1 × 10(5) allogeneic ASCs marked with bromodeoxyuridine were placed in the lesion immediately before suturing. The animals were killed at 12 weeks. RESULTS: In group A (short lesion, acute repair) 6 of 12 ASC-treated menisci and 0 of 12 controls had some healing (P = .014). In group B (short lesion, delayed repair) 2 of 8 ASC-treated menisci and 1 of 8 controls had some healing (P = .5). In group C (long lesion, acute repair) 6 of 12 ASC-treated menisci and 0 of 12 controls had some healing (P = .014). In group D (long lesion, delayed repair) 4 of 8 ASC-treated menisci and 0 of 8 controls had some healing (P = .07). The addition of ASCs increased the healing rate (odds ratio, 32 [range, 3.69 to 277]; P = .002). The histologic analysis of the healed zones identified well-formed meniscal fibrocartilage with persistence of cells derived from the ASCs (immunolocated with anti-bromodeoxyuridine antibodies). CONCLUSIONS: Adding ASCs to a repair in the avascular zone of rabbit menisci increases the chances of healing. Healing is improved in small and larger lesions. When suture is delayed, the effect is not as evident. CLINICAL RELEVANCE: In the future, ASCs might help in meniscal repair in the avascular zone.