Synovial metaplasia of the skin.
ABSTRACT Synovial metaplasia has been described in bone or soft tissues following surgical procedures or under experimental conditions. Three cases in which skin biopsies showed synovial metaplasia of the dermis are herein reported. The metaplastic foci were associated with cyst formation and transepidermal fistulae. All patients had a history of previous surgical procedures in the area, and in all, the lesions clinically resembled suture granulomas. Microscopically, the lesions bore a striking resemblance to hyperplastic synovium. The immunohistochemical studies showed strong staining with vimentin and scattered positivity with alpha-1-antichymotrypsin (alpha-1ACT) and lysozyme. No basement membrane antigens or elastic fibers were demonstrated. We believe that the name "metaplastic synovial cyst" is an appropriate pathologic designation for this entity. An increased awareness of its occurrence will help to establish its true incidence.
Article: Cutaneous metaplastic synovial cyst.[Show abstract] [Hide abstract]
ABSTRACT: Metaplastic synovial cyst, a recently described entity, is histologically characterized by a cystic cavity lined by metaplastic synovial tissue that is often hyperplastic and protrudes into its lumen as villous structures. Clinically, these lesions resemble suture granuloma and develop at the site of previous surgical trauma. We have studied 4 cases of this unusual entity and have investigated the immunohistochemical profile in an effort to determine the nature and derivation of their lining tissue. One of our cases is unique since the lesion was associated with a basal cell carcinoma. A history of previous surgery was noted in one, and history of trauma in 2 of the 4 cases. Our immunohistochemical observations confirmed a mesenchymal derivation for the "synovial like villous structures" but non-availability of a specific "synovial" marker does not permit us to conclude with certainty the synovial nature of the metaplastic tissue. Cutaneous metaplastic synovial cysts are unique lesions which deserve attention and should be included in the differential diagnosis of cutaneous cysts.Journal of Cutaneous Pathology 03/1990; 17(1):22-6. DOI:10.1111/j.1600-0560.1990.tb01673.x · 1.56 Impact Factor
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ABSTRACT: There is scanty knowledge of the morphology of peritoneal dialysis catheter tunnels in humans, even though such knowledge may impact on peritoneal catheter design, implantation and postimplantation care. Past descriptions of catheter tunnels are based mainly on data from animal experiments. Based on these data, it has been assumed that epidermal spreading is inhibited by collagen fibers ingrown into the cuff. Our preliminary investigation indicated that this may not be the case in humans and led us to study catheter tunnel morphology in more detail. Eighteen catheter tunnels (2-5mm of tissue around the catheters) were removed in 17 peritoneal dialysis patients. The catheters were inserted 30 to 2013 days prior to removal (median 366 days). The catheters were removed electively or because of infectious or noninfectious complications. Contrary to the observations in animals, in only 1 case did epithelium extend to the cuff with only a minimal amount of granulation tissue present at the end of a 9 mm long sinus tract. In the remaining cases, the leading edge of the epithelium always met granulation tissue 1-14 mm from the exit, and the cuffs were found 8-33 mm from the exit. In tunnels older than 197 days, dense fibrous tissue was ingrown into the cuffs, and a dense fibrous capsule surrounded the cuff. The uninfected intercuff segment formed a pseudosheath, indistinguishable from a tendon sheath or synovial membrane. Infection in the catheter tunnel propagates through the part of the cuff adjacent to the tubing inside the capsule, suggesting that the cuff per se does not constitute a major barrier for spreading infection. This observation, by exclusion, infers that the beneficial role of an external cuff in decreasing exit infections is by providing firm anchorage of the catheter resulting in restriction of its piston like movement and thereby minimizing trauma and inward conveyance of outer sinus tract flora.Peritoneal dialysis international: journal of the International Society for Peritoneal Dialysis 02/1991; 11(3):237-51. · 2.20 Impact Factor
Article: Synovial metaplasia of the skin.[Show abstract] [Hide abstract]
ABSTRACT: We present two female patients, aged 15 and 45 years, with synovial metaplasia of the skin. Both lesions, localized in the knee and hand respectively, arose after preceding local trauma. Case 1 had intradermal irregular cystic spaces in the adjacent myxoid stroma of which large polygonal eosinophilic cells were found. In contrast, case 2 was characterized by a longitudinal space within the lower dermis and subcutis which was lined by a membrane similar to hyperplastic synovium. The cells of the membrane showed an eosinophilic spindle shaped cytoplasm with processes towards the lumen. In both cases the eosinophilic cells, strongly suggestive of fibroblasts, showed staining for vimentin only, whereas no reactivity could be obtained with antibodies to actin, desmin, S-100 protein, Factor VIII related antigen, cytokeratin, epithelial membrane antigen, carcinoembryonic antigen and CD 68. The absence of CD 68 positivity differs from that seen in normal and hyperplastic synovium. Delayed wound healing around a nidus seems the most likely cause of the change.Virchows Archiv. A, Pathological anatomy and histopathology 02/1993; 423(4):315-8.