Initial Excision Research Articles

Review of Tumor Margins for Lentigo Maligna with Staged Surgical Excision and Permanent Section en face Processing

Background: The optimal surgical margins required for the excision of lentigo maligna remains a topic of debate. Recent literature suggests that wider margins are warranted. Objective: Comparison of lentigo maligna margin sizes and clearance rates from a single center to existing literature. Methods: A retrospective analysis of primary and recurrent lentigo maligna treated by staged excision with complete circumferential and deep margin assessment between 2011 and 2023 at a single institution was conducted. The percentage of tumors with clear margins after the initial excision with 5 mm margins was determined. Results: A total of 65 tumors were identified. Fifty-eight patients (89.2%) had clear margins after initial excision with 5 mm margins. Conclusions: This study reports a higher percentage of lentigo maligna clearance following the initial staged excision with 5 mm margins than reports in the literature. These differences may be attributed to variations in section processing, staining techniques, and factors associated with differences in subclinical spread.

Detection of molecular residual disease in stage II and III melanoma utilizing circulating tumor DNA.

e21564 Background: Overall survival for patients with melanoma has significantly improved with advancements in immunotherapy, especially with immune checkpoint inhibitors and BRAF/MEK inhibitors becoming standard of care for advanced melanoma. However, the decision to proceed with adjuvant therapy should be considered against the risk of adverse side effects, particularly in early-stage melanoma patients. Accurate biomarkers are needed to risk stratify patients, determine who will most likely benefit from adjuvant therapy, and identify when the ideal time is to initiate treatment. This study evaluates the prognostic value of personalized, tumor-informed circulating tumor DNA (ctDNA) testing in patients with stage II and III melanoma. Methods: In this real-world study, plasma samples (n =429) were analyzed from 90 stage IIA-IIID cutaneous melanoma patients treated at Rush University Medical Center between 03/30/2021 and 01/30/2024. A clinically-validated, personalized, tumor-informed 16-plex PCR assay (SignateraTM, Natera, Inc.) was used for detection and quantification of ctDNA in plasma samples. Results: Personalized, tumor-informed ctDNA assays were created using tissue samples from either initial biopsy or surgical excision specimen. Assay design was successful for 100% (90/90) of patients with sufficient tissue; test requests for 4 patients could not proceed due to insufficient tissue. ctDNA was detectable in 28% (25/90) of patients at one or more time points. There was a higher ctDNA-positivity rate in stage III patients (20/50, 40%) compared to stage II patients (5/40, 13%). Of the 25 patients with identifiable ctDNA during surveillance, 13 tested positive on the initial test (2 stage II and 11 stage III). Eighteen of the 25 ctDNA-positive patients received immunotherapy; eight patients achieved sustained ctDNA clearance, 2 had transient clearance, 2 have remained positive on ctDNA testing, and 6 continue to receive adjuvant IO and follow-up ctDNA testing. Clinical or radiographic recurrence occurred in 11/90 patients, 10 of whom tested positive for ctDNA. Conclusions: Personalized, tumor-informed ctDNA offers an adjunct to conventional monitoring for melanoma patients to detect molecular residual disease and was found to be prognostic in our patient cohort. Prospective studies are needed to evaluate the role of ctDNA in clinical decision making for surveillance imaging intervals and appropriate initiation, intensification, or discontinuation of adjuvant therapy.

Early Complications of Planned Resection Versus Unplanned Excision of Sarcomas in the Distal Upper Extremity

Unplanned excisions are defined as excisions of malignant tumors performed without preoperative cross-sectional imaging or diagnostic biopsy, frequently resulting in residual disease and re-excision secondary to positive surgical margins. The purpose of this study was to compare the relative morbidity of planned versus unplanned upper-extremity sarcoma excisions. A single tertiary referral hospital pathology database was queried from January 2015 through 2022 for primary upper-extremity sarcomas (forearm, wrist, hand, and finger). Demographics, tumor features, survival characteristics, and outcomes were retrospectively reviewed. Forty-two upper-extremity sarcoma patients were identified, two-thirds of whom had unplanned excisions. Those with unplanned excisions were more likely to be female (relative risk [RR]: 1.9; P= .002), undergo initial excision at a nonsarcoma center (RR: 14.0; P < .001), have masses distal to the forearm (RR: 1.6; P= .02), and have smaller masses (4.8 vs 7.4 cm, P= .03). 71.4% of tumors were high grade, and 60.7% less than 5 cm in size.Unplanned excisions had positive margins in 96.4% of cases and were more likely to undergo re-excision (odds ratio [OR]: 20.0; P= .001), more total resections (2.7 vs 1.4, P= .009), sacrifice of neurovascular structures (OR: 6.1; P= .04), adjuvant radiation therapy (OR: 4.5; P= .05), adjuvant systemic therapy (OR: 10.9; P= .03), or experience a complication (OR: 17.6; P= .002) at an average of 38.0 months of follow-up.Nearly half of all unplanned excision patients developed a local recurrence or metastatic disease. Six patients required an amputation versus one in the planned cohort (P= .17), and 26.5% of patients died at an average of 32.5 months from presentation. Distal upper-extremity sarcoma excisions are frequently unplanned, with high rates of morbidity compared with planned excisions. Surgeons should have a low threshold for cross-sectional imaging and core needle biopsy of atypical lesions, irrespective of size, with referral to a sarcoma center. Prognostic IV.

Dermatofibrosarcoma of Darrier and Ferrand: Recurrency Character: A Case-Report (Experience of the University Hospital Tangier-Tetouan-Al Hoceima)

Introduction: Dermatofibrosarcoma of Darier and Ferrand (DFSP) is a rare skin tumor characterized by its local aggressiveness and high potential. Its prognosis depends essentially on the quality of its management. Observation and Results: In this article, we report the case of a young patient treated at the Department of Plastic, Reconstructive and Aesthetic Surgery, Tangier, for a Darier and Ferrand dermatofibrosarcoma that recurred five times after surgical excision, with a 5-cm margin on the surface and a healthy anatomical barrier at depth. Coverage of the loss of substance (LOS) was performed after anatomopathological confirmation of the carcinological nature of the excision, and essentially involved skin grafting. Despite a course of radiotherapy prescribed at the 4th recurrence, a 5th rapid recurrence was noted. Discussion: The great clinical, histological and evolutionary polymorphism of this type of sarcoma results in an underestimated incidence and explains the delay in diagnosis. Recurrences are frequent, and usually local. Initial wide surgical excision is the reference treatment, and directly conditions the prognosis of DFSP. According to several studies, recurrence may depend on the quality of surgical excision, but could also be attributed to genetic or environmental factors, or to variations in the histological subtype of the sarcoma. Conclusion: Darier Ferrand is an uncommon tumor with local malignancy, whose evolutionary risk depends mainly on the quality of the initial excision. The chances of cure in the case of well performed primary surgery are significantly higher than in the case of salvage surgery. Tumor excision must the refore be wide and deep, with sacrifice of a healthy barrier at depth.

The significance of BAP1 and MTAP/CDKN2A expression in well-differentiated papillary mesothelial tumour: a series of 21 cases and a review of the literature

The nomenclature and diagnostic criteria of well-differentiated papillary mesothelial tumour (WDPMT) have been changed in the 2021 World Health Organization (WHO) classification of thoracic tumours, and a new entity, mesothelioma in situ (MIS), introduced. Histologically these two entities may be similar. However, MIS is regarded as a precursor to invasive mesothelioma and requires demonstration of loss of BAP1 and/or MTAP/CDKN2A for diagnosis, whereas performance of these ancillary tests is desirable but not essential for a diagnosis of WDPMT, in which the significance of BAP1 and/or MTAP/CDKN2A loss is not well understood or well defined. Against this backdrop, we undertook an investigation of 21 cases of WDPMT, identified from our case files and diagnosed according to 2021 WHO criteria, to explore the relationship between histology and BAP1 and MTAP/CDKN2A expression with clinical features including asbestos exposure, focality of tumours and clinical outcome. There were 18 women and three men, with ages ranging from 23-77 years (median 62 years), in which six had a history of asbestos exposure, two had no exposure, and in 13 exposure history was unavailable. Of 20 peritoneal tumours and one pleural tumour, 13 were detected incidentally at the time of surgery for unrelated conditions and eight peritoneal tumours were multifocal at the time of diagnosis. BAP1 immunohistochemistry (IHC) was performed in all 21 tumours, with nine tumours showing BAP1 expression loss. MTAP/CDKN2A testing was performed in 14 tumours, comprising MTAP IHC in 12 and CDKN2A fluorescence in situ hybridisation (FISH) in two, with three tumours showing MTAP/CDKN2A expression loss. Two tumours with MTAP/CDKN2A loss also showed BAP1 expression loss. Four patients progressed to invasive mesothelioma, including one male with a pleural tumour and asbestos exposure, and three females with multifocal peritoneal tumours, two with asbestos exposure and one without exposure. BAP1 expression loss was seen in all tumours from the four patients who progressed to invasive mesothelioma, whilst two of these tumours showed retained MTAP IHC and two were not tested. There was one patient with a tumour with MTAP loss and retained BAP1 who died from unrelated causes 5 months after diagnosis. Eight patients received WDPMT-specific treatment in addition to the initial excision. Survival for all patients ranged from 4-218 months, with one patient dying of mesothelioma at 49 months. Based on our results in this series of 21 patients with WDPMT diagnosed according to 2021 WHO criteria, we propose that WDPMT with BAP1 expression loss may best be regarded as papillary MIS and that a history of asbestos exposure and the presence of multifocal tumours in patients diagnosed with WDPMT should prompt ancillary testing with BAP1 IHC. Further we propose that BAP1 IHC should be essential in the diagnosis of WDPMT, with the diagnosis restricted to those tumours which show retained BAP1 expression. However more studies in larger cohorts of patients are needed to explore the relationship between BAP1 expression and MTAP loss in WDPMT, which will help to define this entity and separate it more clearly from MIS and invasive mesothelioma.

Abstract PO2-21-01: Granular Cell Tumors of the Breast: A Case Series

Abstract Objective: Granular cell tumors (GCT) of the breast are rare, Schwann-cell derived tumors that are largely benign in nature, but may present with malignant characteristics in 1-2% of cases. There are few reports highlighting the clinical presentation, cytologic differences, operative management and clinical outcomes of patients with these benign versus malignant GCTs. Here, the authors report the clinical course of 9 patients identified with either benign or malignant GCT of the breast. Methods: The medical records for a total of 9 patients treated for histologically confirmed GCT of the breast between March 2015 and May 2023 at our institution were retrospectively reviewed. Clinical data, imaging findings, immunohistochemical markers, surgical interventions, and clinical follow-up data were collected and analyzed. Results: All patients were female, with a mean age of 46 years (Range: 29-61). 5 (56%) patients presented with left-sided lesions with an average maximum dimension of 1.1 cm (SD: 0.7 cm). All 9 (100%) tumors were positive for S100, 4 (44%) were positive for CD68, and 3 (33%) were positive for Inhibin. 4 (44%) patients underwent local mass excision, 3 (33%) underwent lumpectomy, 1 (11%) underwent lumpectomy with sentinel lymph node biopsy, and 1 (11%) underwent partial mastectomy with sentinel lymph node biopsy. There were no perioperative complications nor complications noted at postoperative follow up visits. 1 patient (11%) had 2 recorded recurrences of GCT after the initial breast mass excision, with each tumor exhibiting different positive immunohistochemical markers. 1 (11%) patient had a previous history of breast cancer at time of GCT diagnosis, and 1 (11%) patient had concurrent breast malignancy with the granular cell tumor being in the lymph node of the same breast. Conclusions: Granular cell tumors of the breast are rare Schwann cell derived tumors that often present near breast scar tissue as spiculated, ill-defined masses with microcalcifications on radiologic imaging, mimicking breast malignancy, leading to overtreatment. This study found that for GCTBs that present in lymph nodes, regardless of low malignant potential seen histologically, there was a higher risk of recurrence, and may require further workup and close follow up after wide local excision. For all other granular cell tumors presenting with normal appearing lymph nodes on imaging, a local mass excision was adequate in management, with low risk of recurrence or malignant potential. Future studies should be performed analyzing long-term follow up for these patients to determine risk of recurrence over longer periods of time, and risk for breast malignancy. Granular Cell Tumor Characteristics Tumor characteristics including laterality, tumor location, maximum dimension in centimeters, and positive immunohistochemistry markers were shown for each patient. Citation Format: Shwetha Kochi, Madeline Karsten, Monika Masanam, Teagan Thorson, Roshanak Derakhshandeh, Patricia Wehner, Lucy De La Cruz, Jennifer Son. Granular Cell Tumors of the Breast: A Case Series [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-21-01.

Recurring Hidradenocarcinoma of the Lower Extremity

ABSTRACT Hidradenocarcinomas are rare adnexal tumor of the sweat glands. They are typically found on the head and neck with a high rate of recurrence and metastasis. Here, we present a case of a 67-year-old woman who presented with long-standing subcutaneous mass over her right knee. She underwent initial surgical excision with positive margins, and histopathology of the resection specimen was consistent with hidradenocarcinoma. The patient completed 60-Gray adjuvant radiation to the surgical bed postoperatively. Eight months later, the patient returned with a concern for recurrence of the hidradenocarcinoma at the same site. Biopsy confirmed the recurrence, and the malignancy was excised with 2-cm margins along with surgical reconstruction with a local muscle flap. She has not had recurrence at follow-up 1 year after the reconstructive flap. This case highlights the histopathologic nature of hidradenocarcinomas and that, despite local excision and large-dose radiation, malignancy can recur.

Squamous Cell Carcinoma of the Lip: Clinical Presentation and Management Outcome

Background: Squamous cell carcinoma (SCC) is the second most common amongst skin cancers, following the basal cell carcinoma. SCC of the lip carries relatively better prognosis if detected early and treated adequately. Public awareness about the significance of early presentation would help to improve the outcome of management. Objective: The current study was conducted to determine the clinical presentation of lip SCC and management outcome with surgery as the primary treatment modality. Methods: This descriptive study was carried out at the National Institute of Rehabilitation Medicine, Islamabad over a period of seven years. All patients who presented with lip SCCs during the study period were prospectively included in the study. Non-consenting patients were excluded. The lesions were excised with 1-2-cm palpable macroscopic safety margins. Results: Out of 37 patients, there were 28 (75.67%) males and 9 (24.32%) females. The ages ranged between 47-79 years with a mean of 59.91±9.17 years. Lower lip was the most commonly affected site (n=30; 81.08%). The duration of the lesions at first presentation varied from 6-13 months with a mean of 7.32±1.79 months. Majority (n=31; 83.78%), of the patients had early stage (stage I and II disease) whereas 6(16.21%) patients had stage III disease. The margin clearance rate after initial excision of the lesions was 91.89%. Karapandzic flap was employed as reconstructive tool among 15(40.54%) patients. The 5-year overall survival rate was 62.16%. Conclusion: Lip SCCs were found more frequently among males aged over 50 years. Lower lip was the commonest seat of lip SCCs. Surgical excision with recommended safety margins was associated with tumor free margins in 91.89% cases. Karapandzic flap was the most useful reconstructive tool. The 5-year overall survival rate was 62.16%.

Total Knee Replacement of Synovial Haemangioma of The Knee Joint in a 44-Year-Old Male: A Case Report

Introduction: Synovial hemangioma is a rare illness frequently misdiagnosed, leading to years of inaction. In this study, we aim to discover the consequences of untreated hemangioma of the knee joint. Case Presentation: Our patient was a 44-year-old male who experienced recurring pain in his left knee. The previous year, the patient experienced pain in his left knee while walking, which has subsided with rest. Although he has been performing radiography at multiple hospitals since 2019, no problems have been recorded. We detected a mass after performing magnetic resonance imaging. The T1-weighted sequence + contras near the medial femoral condyle revealed a homogeneous mass with high intensity. We decided to conduct surgical intervention and total knee replacement. Postsurgical, the patient regained symptom-free. Conclusions: Because of the limited radiographic capacity, synovial hemangioma is uncommon and challenging to diagnose on an outpatient basis. Magnetic resonance imaging and angiography are highly beneficial. If intraarticular hemangiomas are not considered, they can cause bony dysplasia and multiple clinical manifestations. Initial total excision can be conducted to decrease the chance of hemarthrosis.

Medical Maintenance Therapy Following Laser Excision in Patients With Granulomatosis With Polyangiitis (GPA)-Associated Subglottic Stenosis.

To report on a series of patients with cANCA/PR3-positive, granulomatosis with polyangiitis (GPA)-associated subglottic stenosis (SGS) and evaluate response to medical maintenance therapy with rituximab versus other immunosuppressants following initial endoscopic laser excision. Retrospective chart review. Tertiary academic center. A retrospective chart review of patients with SGS and cANCA/PR3-positive GPA who received immunosuppressive maintenance therapy following endoscopic laser excision at our institution from June 1989 to March 2020 was performed. Data pertaining to patient demographics, clinical features, medications, and endoscopic laser procedures were collected. A total of 27 patients (15 women) with mean age (range) of 40 (19-59) years and mean (range) follow-up of 12.6 years (1.5-28.6) were identified. Sixteenpatients (60%) had limited GPA. Six patients (24%) had previously received local intervention with open surgery (n = 1, 4%) or endoscopic techniques (n = 5, 20%). All patients experienced symptom improvement following initial CO2 laser excision at our institution without any procedural complications or adverse events. Following initial laser excision, 15 patients (60%) were treated with rituximab and 10 patients (40%) were treated with nonrituximab immunosuppressive agents. Patients treated with rituximab were less likely to recur (P = 0.040). Limited GPA was associated with an increased incidence of recurrence (P = 0.031). Median time (years) to recurrence (range) was 3.2 (0.3-19.3) and was not significantly associated with treatment or GPA subtype. Endoscopic CO2 laser excision is a safe and effective local intervention for GPA-associated SGS. Medical maintenance therapy with rituximab reduces risk of recurrence following initial laser excision relative to treatment with non-rituximab agents.

Tuberculosis Mimicking-Musculoskeletal Tumor of The Hand: An Uncommon Case of Extrapulmonary Tuberculosis

Background: Musculoskeletal extrapulmonary tuberculosis is accounting for only 10-15% of all cases. Current attention has been focused on hand tuberculosis due to its increasing prevalence. This study describes an unusual case of extrapulmonary tuberculosis that manifested as a soft tissue tumor of the hand.Case Report: A 17-year-old male presented with a painful swollen part of the 3rd finger of the left hand. The mass was irregular and suppurative, with discoloration and foul smell. Laboratory results showed anemia and increased erythrocyte sedimentation rate. The computed tomography scan showed an isodense soft tissue (size 2.19 cm x 1.59 cm x 4.21cm) across the distal to the proximal part of 3rd phalanx bone to the metacarpal region with a decrease of phalanx bone density with no sign of bone destruction or any periosteal reaction. The histopathology study revealed a chronic granulomatous structure surrounded by epitheloid cells, datia Langhans cells, and caseating necrosis. The acid-fast staining confirmed the presence of bacilliform bacteria.Discussion: Extrapulmonary tuberculosis typically results from secondary hematogenous dissemination and reactivation of the main foci. There are no specific tests to diagnose musculoskeletal tuberculosis preoperatively, leading to delayed diagnosis. Histopathological examination and culture are needed to confirm the diagnosis.Conclusions: Slow progression and multiple differential diagnoses frequently result in a delayed diagnosis, which leads to complications. Initial radical excision and anti-tuberculosis multidrug therapy provide excellent functional outcomes and recurrence prevention.

Surgical outcomes for cutaneous squamous cell carcinoma of the auricle.

Cutaneous squamous cell carcinoma (CSCC) on the auricle is believed to carry a higher risk of metastatic spread. The rates of lymphatic metastasis reported in the literature have varied widely. There are no established prognostic criteria to determine which of these tumors are higher risk and warrant prophylactic treatment of the associated lymphatic basins. To retrospectively evaluate outcomes after surgical treatment of auricular CSCC in our department, examining excision completeness, tumor recurrence, and lymphatic metastasis. Secondarily, to identify factors associated with lymphatic metastasis. One hundred and thirty-eight consecutive cases of auricular SCC were excised from 126 patients in our department over a 7-year period (January 2012-December 2018). Data were retrospectively collected on patient characteristics, tumor histology, surgical procedures, and follow-up. Incomplete initial excision occurred in 17 cases (12.32%). Six patients (4.76%) had a local recurrence. Lymphatic metastasis occurred in eight patients (6.35%), on average within 10.25 months after primary excision. Six patients with metastasis died during follow-up, with a mean survival of 10.2 months. Older age was associated with lymphatic metastasis (P = 0.0267). Other factors, including tumor recurrence, size, grade, cartilage invasion, and positive margins, were evaluated and not significantly associated with metastasis. In this study, the metastatic rate of auricular SCC was 6.35%, which is within the previously reported ranges. No histological prognostic factors were identified in this study, which may be due to our limited sample size. In the absence of established prognostic criteria, decisions regarding prophylactic treatment should be made on an individual basis with multidisciplinary support.

Surgical and biochemical outcomes of phosphaturic mesenchymal tumors causing tumor-induced osteomalacia in the head and neck region

ObjectivesWe aimed to report the surgical outcomes of phosphaturic mesenchymal tumors causing tumor-induced osteomalacia in the head and neck. MethodsThis study analyzed nine patients who underwent surgical excision of phosphaturic mesenchymal tumors in the head and neck region. The primary sites were two in the maxilla and ethmoid sinus, and one in the intracranial, skull, parotid gland, maxillary sinus, and nasal cavity in each patient. Outcomes were compared with those in the extremities and trunk (n = 32). ResultsFive of nine patients (56%) developed residual disease/local recurrence associated with low serum phosphate level after initial surgical excision. At the last follow-up, the biochemical parameters were normalized in four of the five patients after re-excision without any medication. The local recurrence/residual disease risk was significantly higher for the head and neck compared with the extremities and trunk (56% vs. 25%, p = 0.048). The rate of remission (normalized serum phosphate without medication) at final follow-up was similar in both groups after re-excision (head and neck vs. extremities and trunk, 86% vs. 73%, p = 0.827). ConclusionsPhosphaturic mesenchymal tumor resection in the head and neck region was challenging because of its complex anatomy and proximity to the brain or other crucial organs, which was associated with high local recurrence/residual disease rate. However, biological remission was achieved in the majority of the patients after re-excision.

Optimal timing of re-excision in synovial sarcoma patients: Immediate intervention versus waiting for local recurrence.

To investigate the difference in efficacy of re-excision in synovial sarcoma patients with and without residual tumor following unplanned excision, and to compare the prognostic outcomes of immediate re-excision versus waiting for local recurrence. This study included synovial sarcoma patients who underwent re-excision at our center between 2009 and 2019, categorized into groups based on unplanned excision and local recurrence. Analyzed endpoints included overall survival (OS), local recurrence-free survival (LRFS), and distant relapse-free survival (DRFS). Prognostic factors associated with these three different survival outcomes were analyzed through the use of Kaplan-Meier curves and Cox regression approaches. In total, this study incorporated 109 synovial sarcoma patients, including 32 (29.4%) with no residual tumor tissue identified after re-excision, 31 (28.4%) with residual tumor tissue after re-excision, and 46 (42.2%) with local recurrence after initial excision. Patients were assessed over a median 52-month follow-up period. The respective 5-year OS, 5-year LRFS, and 5-year DRFS rates were 82.4%, 76.7%, and 74.2% for the nonresidual group, 80.6%, 80.4%, and 77.3% for the residual tumor tissue group, and 63.5%, 50.7%, and 46.3% for the local recurrence group. There was no significant difference in OS of nonresidual group and residual group patients after re-excision (p = 0.471). Concurrent or sequential treatment with chemotherapy and radiotherapy significantly reduced the risk of metastasis and mortality when compared with noncombined chemoradiotherapy, and was more effective in the local recurrence group (p < 0.05). Prompt and adequate re-excision is crucial for patients with synovial sarcoma who undergo initial inadequate tumor excision, and their prognosis is significantly better compared with patients who delay re-excision until local recurrence.

Cutaneous leiomyosarcoma: a retrospective review of45cases.

Primary cutaneous leiomyosarcoma (LMS) is a rare soft tissue tumour type with two subtypes, dermal and subcutaneous. As deeper tumours confer a worse prognosis, they require a more aggressive approach. Conversely, a more conservative surgical approach for dermal LMS has been suggested. Few studies have comprehensively reported both clinical surgical and histological excision margins. Therefore, we sought to provide margin recommendations based on our experience and review of the existing literature. We undertook a retrospective case-note review (1998-2019) of cutaneous LMS management to establish histological/surgical margins using pathology/electronic patient records. The diagnosis was made and classified by an experienced dermatopathologist according to the World Health Organization classification. In the dermal LMS cohort (n = 35), mean peripheral and deep histological margins were 5.4 mm (range 0.5-20) and 5.6 mm (range 0.1-14.5), respectively. The incomplete excision rate was 31% (11 of 35). There were no recurrences. In the subcutaneous LMS cohort (n = 10), mean peripheral and deep histological margins were 5.7 mm (range 0.2-14) and 1.1 mm (range 0.2-1.7), respectively. The incomplete excision rate was 40% (4 of 10). The recurrence rate was 20% (2 of 10) despite achieving histological clearance after 1 year. One lung metastasis occurred 1 year following an adequately excised primary scalp LMS. Thus, for dermal LMS we propose a clinical margin of 5-10 mm (depending on lesion size) at the initial excision or at scar re-excision following involved/close histological peripheral and/or deep margins (i.e. < 1 mm). For subcutaneous LMS, we suggest a clinical margin of 15-20 mm (depending on lesion size) to achieve a peripheral histological clearance of 10 mm and negative deep margin (i.e. > 1 mm), down to the periosteum/fascia/muscle according to anatomical site. If this is not achieved, a re-excision would be recommended. However, prospective studies are needed for optimal guidance.

DP26 Syringocystadenocarcinoma papilliferum masquerading as squamous cell carcinoma

Abstract Syringocystadenocarcinoma papilliferum (SCACP) is a rare cutaneous adnexal neoplasm with ~30 cases reported. This case highlights the potential diagnostic and treatment challenges. A 52-year-old woman presented with a poorly differentiated carcinoma on the left parietal scalp which recurred 2 and 5 years following the original surgical excision. Initial biopsy of this lesion had shown syringocystadenoma papilliferum (SCAP) with associated syringoma, and a subsequent wider excision revealed suspected poorly differentiated squamous cell carcinoma (SCC) in the deeper dermis that was fully excised; however, the SCAP reached the margins. Excision 2 years later of the first recurrence showed similar histological features, and a second recurrence was excised twice to achieve histological clearance followed by postoperative radiotherapy. She remains tumour-free 2 years later. Upon retrospective review of all specimens, the initial primary tumour excision showed histological findings of a surface exophytic SCAP with mild nuclear enlargement, nucleoli and scattered mitotic figures. An infiltrative lesion was seen beneath this consisting of atypical ductal structures within a fibroblastic stroma. In deeper regions, there was more solid proliferation with some squamous differentiation, although scattered glandular units remained visible. However, the squamous component was predominant in future biopsies and even represented the sole morphological appearance in some. This culminated in the latest biopsy showing a poorly differentiated spindle cell tumour which, with immunohistochemistry (BerEP4-negative; cytokeratin, CK14−, CK5−, p63− and p53-positive; and high Ki67 index), was considered entirely to be a poorly differentiated SCC. Ultimately, this sequence of biopsies actually represented the rare diagnosis of SCACP, which demonstrated progressive squamous differentiation with each recurrence. A previous case published also reported SCACP transition to squamous differentiation (Zhang YH, Wang WL, Rapini RP et al. Syringocystadenocarcinoma papilliferum with transition to areas of squamous differentiation: a case report and review of the literature. Am J Dermatopathol 2012; 34:428–33). Despite the generally favourable prognosis reported, there have been a few cases of locoregional metastasis. Furthermore, recurrence up to 8 years after excision of the primary tumour has been reported (Castillo L, Moreno A, Tardío JC. Syringocystadenocarcinoma papilliferum in situ: report of a case with late recurrence. Am J Dermatopathol 2014; 36:348–52). We present a unique case of doubly recurrent SCACP managed with surgery and adjuvant radiotherapy which highlights the need for long-term follow-up. Furthermore, SCACP may pose a diagnostic challenge due to squamous differentiation of these tumours, which may result in incorrect or delayed diagnosis.

Multiple local recurrences of primary sternal chondrosarcoma: tumor manipulation or self-seeding

BackgroundPrimary sternal chondrosarcoma, although rare, is the most common malignant tumor of the sternum. The gold standard treatment is complete surgical excision, which frequently causes the instability of the thorax necessitating future reconstruction. Local recurrence is common increasing the risk of distant metastasis.Case presentationA 60-year-old male patient was diagnosed with primary sternum chondrosarcoma and underwent surgical excision with negative resection margins. Later, he was found to have two local recurrences at 11 months and 37 months post initial excision. The two recurrences were surgically removed followed by local adjuvant radiation.ConclusionThe seeding theories have been reported more frequently with relation to diagnostic biopsy procedures, tumor manipulation and self-seeding tumors. The patient developed two local recurrences despite total resection with negative margins, without concerns regarding seeding in distant metastasis.

Cross‐finger flap as ultima ratio for the reconstruction of defects of the finger flexor sides

Cross‐finger flap as ultima ratio for the reconstruction of defects of the finger flexor sides

GAB1::ABL1 fusions define a distinctive soft tissue neoplasm, with variable perineurial differentiation, and a predilection for children and young adults.

Although well known as a fusion partner in hematological malignancies, fusion genes involving the ABL proto-oncogene 1 (ABL1), mapping to chromosomal region 9q34.12, have only been anecdotally reported in five soft tissue tumors. These neoplasms have been variously reported as perineurioma, angiofibroma, and solitary fibrous tumor, and all have harbored a GAB1::ABL1 gene fusion; however, the nosology and clinicopathological characteristics of soft tissue tumors carrying this rare fusion have not been delineated. We herein describe eight tumors containing the GAB1::ABL1 fusion and review previously reported cases in a series to define their morphological spectrum, address immunohistochemical evidence for a line of differentiation, with special reference to the presence or absence of a perineurial immunophenotype, and gather insight into their behavior. The patients included four females and four males, aged 13-37 years (median, 24 years). Two cases each originated in the shoulder area, trunk, hands, and lower extremities, with a size range of 1.5-8cm (median, 3.4cm). Four tumors were deep and four superficial. All tumors were morphologically similar, being composed of bland fibroblast-like spindle to ovoid cells diffusely arranged in a paucivascular fibrous to fibromyxoid stroma with variable resemblance to soft tissue perineurioma. Mitotic activity was generally low (0-8 mitoses in 10 high-power fields [HPFs]; median, 1). All lesions had at least focally infiltrative margins, but they otherwise lacked pleomorphism and necrosis. Immunohistochemistry showed focal reactivity for CD34 (5/7), epithelial membrane antigen (EMA) (3/8), claudin1 (2/3), GLUT1 (4/6), and S100 (2/7); other markers, including MUC4 (0/7), desmin (0/9), and smooth muscle actin(SMA) (0/4), were negative. RNA sequencing revealed a GAB1::ABL1 fusion in all cases with exon 6 of GAB1 fused to exon 2 of ABL1. Treatments included various forms of surgical intervention in seven cases; one tumor was biopsied only. Limited follow-up was available for five patients. One tumor regrew rapidly within 1 month to 1.5cm after an initial marginal excision and was re-excised with close margins. Four patients were disease-free at 1, 3, 14, and 25 months of follow-up. Metastases have not, to date, been observed. This series characterizes "GAB1::ABL1 fusion-positive spindle cell neoplasm" as a distinct entity, with overlapping features with soft tissue perineurioma and predilection for children and young adults.

Is it time we changed the way we manage melanoma in situ of the trunk and limbs?

There is little evidence on the optimal clinical and histological margins required to reduce local recurrence in melanoma in situ (MIS). Our aim was to identify the number of lesions on the trunk and limbs with histological clearance &amp;gt; 1 mm after initial narrow-margin excision. In our cohort 93.6% were considered clear after initial exclusion with no residual MIS seen when further wide local excision was carried out.