Appropriate patient care mandates consideration of perineural invasion in the evaluation of cutaneous tumors. As the majority of patients present without symptoms of neural involvement, physicians must be vigilant in the search for this type of tumor spread.
There are two main types of fungal infections in the oncology patient: primary cutaneous fungal infections and cutaneous manifestations of fungemia. The main risk factor for all types of fungal infections in the oncology patient is prolonged and severe neutropenia; this is especially true for disseminated fungal infections. Severe neutropenia occurs most often in leukemia and lymphoma patients exposed to high-dose chemotherapy. Fungal infections in cancer patients can be further divided into five groups: (i) superficial dermatophyte infections with little potential for dissemination; (ii) superficial candidiasis; (iii) opportunistic fungal skin infections with distinct potential for dissemination; (iv) fungal sinusitis with cutaneous extension; and (v) cutaneous manifestations of disseminated fungal infections. In the oncology population, dermatophyte infections (i) and superficial candidiasis (ii) have similar presentations to those seen in the immunocompetent host. Primary cutaneous mold infections (iii) are especially caused by Aspergillus, Fusarium, Mucor, and Rhizopus spp. These infections may invade deeper tissues and cause disseminated fungal infections in the neutropenic host. Primary cutaneous mold infections are treated with systemic antifungal therapy and sometimes with debridement. The role of debridement in the severely neutropenic patient is unclear. In some patients with an invasive fungal sinusitis (iv) there may be direct extension to the overlying skin, causing a fungal cellulitis of the face. Aspergillus, Rhizopus, and Mucor spp. are the most common causes. We also describe the cutaneous manifestations of disseminated fungal infections (v). These infections usually occur in the setting of prolonged neutropenia. The most common causes are Candida, Aspergillus, and Fusarium spp. Therapy is with systemic antifungal therapy. The relative efficacies of amphotericin B, fluconazole, itraconazole, voriconazole, and caspofungin are discussed. Recovery from disseminated fungal infections is unlikely, however, unless the patient's neutropenia resolves.
background. Perineural invasion is an important mode of tumor spread and is associated with increased aggressiveness and a propensity for recurrence among cutaneous malignancies. objective. To review the pathogenesis, diagnosis, and treatment of cutaneous tumors exhibiting perineural invasion. methods. This article is based on a review of the medical literature concerning tumors with perineural involvement. results. This article describes the clinical signs and histologic features of cutaneous malignancies exhibiting perineural involvement. conclusion. Appropriate patient care mandates consideration of perineural invasion in the evaluation of cutaneous tumors. As the majority of patients present without symptoms of neural involvement, physicians must be vigilant in the search for this type of tumor spread.
It was the purpose of this study to evaluate the clinical long-term effects of PLLA degradation in vivo on nerve regeneration in the rat sciatic nerve model. Thirty-one Sprague Dawley rats were utilized. Two groups of animals were selected. The control group of 10 animals received a 12 mm reversed isograft into the right sciatic nerve from 5 donor animals. The experimental group (n = 21) received a 12 mm empty PLLA conduits placed into a 12 mm defect in the right sciatic nerve. The left leg served as an internal control. Walking track analysis was performed monthly through 8 months. At the end of 4 and 8 months, animals in the control isograft and experimental group had the medial and lateral gastrocnemius muscles harvested and weighed for comparison. The midconduit/isograft and the distal nerve in these same animals were harvested and histomorphologically analyzed. Multiple samples were collected and expressed as means +/- standard error. A two-sample t-test and Wilcoxon rank sum test was used to compare the variables. Significance level was set at alpha = 0.05. After Bonferroni correction for multiple testing, a p value of < or = 0.01 was considered statistically significant. Throughout all time periods, the PLLA conduit remained structurally intact and demonstrated tissue incorporation and vascularization. There was no evidence of conduit collapse or breakage with limb ambulation. Moreover, there was no evidence of conduit elongation at 8 months as previously observed with the 75:25 poly(DL-lactic-co-glycolic acid) (PLGA) conduits. The mean absolute value of the sciatic functional index (SFI) demonstrated no group differences from isograft controls measured over the 8 months except at 3 months where the isograft values were higher (p = 0.0379) and at 7 months were the isograft group was significantly lower (p = 0.0115). At 4 and 8 months, the weight of the gastrocnemius muscles of the experimental group was not significantly different from isografts. At 4 months the number of axons/mm2 and nerve fiber density was not significantly different between the isograft control and experimental groups in either the midconduit/isograft or distal nerve. At 8 months the number of axons/mm2 was significantly lower in the isograft compared to the midconduit experimental group (p = 0.006). The number of axons/mm2 in the distal nerve and the nerve fiber density in the midconduit and distal nerve were not significantly different between the two groups. The study confirmed our initial hypothesis that PLLA conduits are a viable scaffold for clinical long-term nerve gap replacement. We are critically aware however that longer evaluation of polymer degradation is warrented. Further studies on these individual nerve components are continuing, with the ultimate goal being the fabrication of a bioactive conduit that meets or exceeds the functional results of isografts.
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