Defining Double Capsules: A Clinical and Histological Study

Background Macrotextured breast implants are associated with double capsules. There is little agreement as to what defines double capsules, how they present, and whether different degrees of double capsule exist. Objectives This study aimed to define double capsules and report an association between double-capsule type and degree of tissue adherence. Methods Consecutive aesthetic patients undergoing explantation of Biocell (Allergan, Inc., Irvine, CA) implants between May 2018 and November 2018 were included if they were found to have double capsules intraoperatively. Patient demographics, implant characteristics, explantation reason, implant adherence, and intraoperative findings were recorded. Both adherent and double capsules were histologically examined. Data were analyzed by descriptive statistics. Results Eleven patients had 22 Biocell implants explanted during the study period. The average explantation time was 8.0 years. Sixteen implants were found to have some degree of nonadherence, and all areas of nonadherence were associated with double-capsule formation. Double capsules were either partial or complete. The architecture of the inner layer of double capsules varied between an organized capsular layer and a thin area of nascent capsule. Histologically, all capsular specimens demonstrated an overall hypocellular fibrous capsule with scattered chronic inflammatory infiltrates. Synovial metaplasia was present in all capsule types and spaces/cracks in the capsule were disproportionately represented in partially adherent capsules. Conclusions This is the first study to identify a clinical and pathological correlation between double capsules and failed tissue adherence. Double capsules represent a spectrum of inner capsule formation ranging between nascent capsular tissue to a mature inner capsular layer. Level of Evidence: 4

Synovial Metaplasia of the Endometrium

Introduction/Objective Synovial-like metaplasia is well known to accompany breast implants, but it can also rarely be found in the endometrium, associated with intrauterine devices. We present two cases of endometrial synovial-like metaplasia. Methods The hysterectomy specimens were diagnosed at Northwell Health and reviewed at the departmental Consensus Conference. Immunostains for cytokeratin AE1/AE3 were performed on the endometrium. The histopathologic findings were correlated with the clinical information. Results Both patients had had intrauterine devices placed for birth control. One, a 47-year-old female with a family history of Lynch syndrome and newly diagnosed with a corresponding mutation, underwent prophylactic hysterectomy. The second patient, a 50-year-old female with a history of uterine prolapse, was experiencing stress urinary incontinence, for which she underwent supracervical hysterectomy. Both patients had intrauterine devices in place at the time of hysterectomy. Both uteri showed endometrial synovial-like metaplasia. It was associated with a complete absence of the endometrial surface epithelium. The synovial-like cells were eosinophilic, plump and elongated, were palisaded perpendicular to the endometrial surface and were negative for cytokeratin AE1/AE3, which immunostain also confirmed the absence of the endometrial surface epithelium and the presence of some residual deeper endometrial glands. Conclusion Endometrial synovial-like metaplasia is a rare entity described in patients with intrauterine devices. The mesodermal-derived endometrium is apparently able, when exposed to a semi-mobile foreign body, to develop a way to minimize friction by mimicking synovium, similar to the connective tissue facing breast implants. Such surface must be better at withstanding chronic friction than the regular endometrial epithelial surface, leading to this unusual and fascinating change. Since the resulting surface mimics synovium perfectly, both morphologically and immunohistochemically, and serves a very similar mechanical purpose, we propose to call this phenomenon, wherever it is found, “synovial metaplasia” instead of the current term “synovial-like metaplasia.”

Extra and Intra-articular Synovial Chondromatosis

Synovial chondromatosis is not so rare intra-articular condition secondary to synovial metaplasia, that affects the knee joint. Extra-articular synovial chondromatosis however is an extremely rare condition that usually involves the synovial sheath or bursa of the foot or hand. We present two cases of synovial chondromatosis, one intra and one extra-articular. The first case was a 25 year old lady who presented with pain, swelling and restricted range of motion of left knee and was found to have an intra-articular synovial chondromatosis which was treated successfully by joint debridement. The second case was that of a 22 year old man who presented with right knee pain and was diagnosed to have an extra-articular synovial chondromatosis of his right medial hamstring tendon sheath, excision of which resulted in complete relief of symptoms.Keywords: extra-articular, intra-articular, metaplasia, rare, synovial chondromatosis.