Recurrent FOXK1::GRHL and GPS2::GRHL fusions in trichogerminoma.

We report 21 cases of trichogerminoma harbouring previously undescribed FOXK1::GRHL1/2 or GPS2::GRHL1/2/3 in-frame fusion transcripts. Microscopic examination of a preliminary set of five cases revealed well-delimitated tumours located in the dermis with frequent extension to the subcutaneous tissue. Tumours presented a massive and nodular architecture and consisted of a proliferation of basaloid cells. A biphasic pattern sometime resulting in tumour cell nests ('cell balls') was present. Immunohistochemistry demonstrated the expression of cytokeratins (CKs) 15, 17, and PHLDA1. In addition, numerous CK20-positive Merkel cells were detected. RNA sequencing (RNA-seq) revealed a FOXK1::GRHL1 chimeric transcript in three cases and a FOXK1::GRHL2 fusion in two cases. In a second series for validation (n = 88), FOXK1::GRHL1/2 fusion transcripts were detected by RT-qPCR or FISH in an additional 12 trichogerminomas and not in any other follicular tumour entities or basal cell carcinoma cases (n = 66). Additional RNA-seq analysis in trichogerminoma cases without detected FOXK1::GRHL1/2 rearrangements revealed GPS2::GRHL1 fusion transcripts in two cases, GPS2::GRHL2 in one case, and GPS2::GRHL3 fusion transcript in one case. Therefore, our study strongly suggests that GRHL1/2/3 gene rearrangements might represent the oncogenic driver in trichogerminoma, a subset of follicular tumours characterized by immature features and numerous Merkel cells. © 2022 The Pathological Society of Great Britain and Ireland.

The Homodigital Propeller Flap: A New Tool for Fingertip Reconstruction. Surgical Technique, Anatomical Study, and Clinical Relevance.

BACKGROUND: An ideal flap for fingertip injuries should cover a significant loss of substance and avoid joint flexion to prevent later contracture and joint stiffness. In this study, the authors describe a modified homodigital island flap-the homodigital propeller flap-to better meet these requirements. METHODS: An anatomical model of fingertip loss is used to analyze the advancement achieved without flexion of the finger. Twenty-four fresh-frozen fingers were dissected. Wires were inserted to maintain joints in extension. The skin paddle was similar in location to a homodigital island flap. The neurovascular bundle was dissected without exceeding the proximal interphalangeal joint and was released from the proximal half of the paddle. Then, the homodigital propeller flap was rotated 180 degrees to cover the defect. A mixture of India ink and barium sulfate was injected into the pedicle artery after the release of the proximal half of the flap from the neurovascular pedicle to assess residual flap vascularization. India ink highlights the residual subcutaneous vascularization network of the cutaneous paddle. A radiographic study of the flap was then performed to visualize the subcutaneous vascular network of the cutaneous paddle. RESULTS: The homodigital propeller flap achieved an average cutaneous advancement of 18 mm (range, 15 to 22 mm) and allowed full coverage of cutaneous defects for all fingers while maintaining the proximal interphalangeal joint in strict extension. CONCLUSIONS: The homodigital propeller flap is a refinement of the classic homodigital island flap. It allows efficient coverage of fingertip defects because of a large advancement without flexion of the finger, reducing the risk of stiffness.

Anatomical basis of the lateral superior gluteal artery perforator (LSGAP) flap and role in bilateral breast reconstruction.

INTRODUCTION: Deep inferior epigastric perforator (DIEP) flap is one of the gold standards in autologous breast reconstruction. When the abdominal tissue is not available, the superior gluteal artery perforator (SGAP) is often a second option with its drawback, especially the donor-site deformity. Reports have highlighted that a higher and more lateral SGAP flap can be harvested to overcome several drawbacks of the classical SGAP, allowing in the same procedure a body-contouring procedure. In order to set the anatomical basis of this flap, we proposed to study the characteristics of a reliable and easily identifiable superior and lateral perforator of the superior gluteal artery (lateral SGAP (LSGAP)) situated in the region of the lower body-lift resection allowing to perform bilateral breast reconstruction at the same time. MATERIAL AND METHOD: The anatomical study of 50 scans (or 100 buttocks) allows us to set forth a diagnostic assumption on the localisation of the perforator with respect to osseous landmarks (coccyx, iliac crest and great trochanter) which will be verified during the dissection of 10 cadavers (or 20 buttocks) and during the 20 colour Doppler examination (or 40 buttocks). RESULTS: In our computed tomography (CT) scan study, in 96% of cases, the perforator was situated in a circle with a radius≤3 cm with a 95% confidence interval and located at the junction of the proximal third-middle third of the distance summit of the posterior iliac crest (point B), most lateral point of the greater trochanter (point C). This assumption was verified by the cadaveric dissection and in vivo studies. CONCLUSION: Our study sets the anatomical landmarks of the LSGAP flap. This option allows the raising of an SGAP flap avoiding the main drawbacks of this flap and allows harvesting a flap with the tissue that is often discarded during the body-lift procedure.

The keystone design perforator island flap. Part I: anatomic study.

BACKGROUND: The keystone design perforator island flap has been described as a curvilinear shaped trapezoidal design flap that is essentially two V-Y flaps end-to-side. Viability of the flap is thought to be supported by the subcutaneous vascular network and fascial and muscular perforators. The aim of this study was to assess the vascularisation of this flap and the behaviour of the skin paddle when submitted to important traction forces. METHODS: Fourteen flaps were raised after a skin defect was created on various regions of two fresh cadavers. Longitudinal and transversal cutaneous markings allowed analysis of the behaviour of the skin paddle during the course of direct closure and flap mobilisation. Injections of coloured solutions were performed before and after the flap elevation to visualise the vascularisation of the flap. DISCUSSION: The superficial vascular network was always preserved by the blunt dissection of the flap's margins and perforators arising from the underlying muscular tissue were constantly found. The dual vascularisation of the flap was then confirmed. Cutaneous markings showed the skin paddle to remain static in size with advancement of the surrounding tissues to meet the flap. The flap advancement opens a long and narrow defect on the lateral margin, the approximation of which in a V-Y fashion reduces even more the surface to be closed. Elevation of the flap also allows distribution of the tension forces over a greater surface both within the flap as well as the surrounding tissues. CONCLUSION: The vascular reliability of this flap and its versatile design potentially gives it a universal application all over the body.

The keystone design perforator island flap. Part II: clinical applications.

BACKGROUND: This curvilinear- and trapezoidal-shaped flap essentially consists of two conjoined V-Y flaps end to side. The vascular supply is supported by the subcutaneous vascular network and is dependent on fascial and muscular perforators. A review of 15 clinical cases was performed to assess the reliability and versatility of the flap. METHODS: Twelve keystone flaps were performed following excision of skin tumours or post-traumatic defects in various locations, from the head and neck region, the trunk and the limbs. RESULTS: No flap necrosis, even partial, was observed regardless of the site and the type of keystone used. Patients were almost pain free in the postoperative course. The aesthetic results are quite satisfactory, as the flap is aligned locally without evidence of the 'pincushioning' appearance sometimes seen around island reconstructions. DISCUSSION: Elevation of the flap seems to evenly distribute the tensional forces without undermining. The flap is particularly useful in the repair of defects following skin cancer removal. Bulk is not a problem and good skin cover is achieved. CONCLUSION: The presence of perforators and subcutaneous network distributed throughout the body create an environment which makes this flap universally applicable and extremely reliable.

Complications analysis of 266 immediate breast reconstructions.

The purpose of this study was to describe the complications of immediate breast reconstruction, to compare their rates with respect to the surgical procedure and to patient's characteristics, in order to improve surgical indications and patient information. We carried out a retrospective study of 266 immediate breast reconstructions (249 women) over a 12-year period (latissimus dorsi myocutaneous flap with implant 61%, autologous latissimus dorsi myocutaneous flap 15%, subpectoral implant 24%). Mean age was 48 and the median follow-up was seven years (2-14). The overall complication rate was 49% (128), and there were 10 reconstruction failures. The most frequent complications were dorsal seroma 26% (70), capsular contracture 10% (27), skin necrosis 8.3% (22), and haematoma 5.6% (15). The complication rate for immediate breast reconstruction with implant alone (39%) was lower than that associated with latissimus dorsi with or without implant (51%), but the difference was not significant (Chi-square: p=0.07). The risk factors for complications were smoking (skin necrosis, Fisher: p=0.02), obesity (infection, Fisher: p=0.004), and radiotherapy (capsular contracture, Chi-square: p=2.6 x 10(-5)). Smoking was found as the only risk factor of reconstruction failure (Fisher: p=0.015). Capsular contractures were more frequent when implants were used alone (25%) as well as when used along with a flap (6.8%) (Chi-square: p=2 x 10(-5)). Infections were also higher in the non-flap group than in the flap group (Fisher: p=0.02). In our opinion, latissimus dorsi myocutaneous flap with or without an implant is a good compromise between complication risk and necessity of good cosmetic result requirement. These results have led us to delay or contraindicate reconstruction in the case of obesity or heavy smoking. In the case of probable post-operative radiotherapy, we prefer to delay the breast reconstruction.

Microsurgery in microgravity is possible.

The aim of this experiment was to evaluate the feasibility of a microsurgical procedure in the context of microgravity during parabolic flights. The surgical procedure included the sectioning and repair of a rat sciatic nerve and tail artery with 10/0 monofilament sutures. Both procedures were successful. To date, telesurgery cannot be considered during interplanetary spaceflights. If a surgeon is able to perform microsurgery in microgravity, a physician with basic surgery training will be able to perform basic surgical procedures in space flights.