Desmoplastic Small Round Cell Tumor as a Rare Cause of an Incarcerated Epigastric Linea Alba Hernia: A Case Report and Literature Review.

Desmoplastic small round cell tumor is a very rare soft tissue sarcoma with a bleak prognosis and short patient survival. The most common occurrence is in 20-30-year-old men. Our study presents the case report of a 40-year-old patient who was diagnosed with this sarcoma. The first symptom of the illness was an incarcerated epigastric hernia with sarcoma metastasis resembling an intestinal loop in an ultrasound image. The fluorescence in situ hybridization (FISH) method showed a fusion of the EWS and WT1 genes. Systemic palliative chemotherapy using the VDC-IE (vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide) regimen was chosen instead of further surgery due to the disease's generalization. However, the therapy failed to halt the disease progression and was thus terminated after 18 months. The patient's overall survival was 19 months. The rare character of this disease complicates the diagnostics in clinical practice. Nevertheless, rare sarcomas should be considered in patients with non-specific abdominal symptoms, including patients with incarcerated ventral hernia.

Ameloblastoma With the Hybrid Desmoplastic and Plexiform Pattern: A Case Report.

Ameloblastoma is an epithelial odontogenic tumor with a benign nature and demonstrates local aggressiveness. It frequently occurs between the third and fifth decades of life, showing significant gender predilection. While typically displaying a benign growth pattern, it tends to invade and sporadically metastasize locally. Ameloblastoma is predominantly found in the posterior regions. Periodic recur commonly follows insufficient treatment. Hence, conducting thorough identification of tumors and management is crucial to prevent relapse. Complications and improved prognosis are associated with meticulous surgical techniques, regular follow-up care, and early detection of recurrence. This study presented a report of a 19-year-old male with swelling in the left lower jaw, detailing its area of complaint, radiographic findings, histopathologic characteristics, and different treatment approaches. The uniqueness of the case is the hybrid histopathology of ameloblastoma composed of plexiform and desmoplastic variants.

Report of Basal Cell Carcinoma Occurring With a Desmoplastic Trichilemmoma Successfully Treated With Mohs Micrographic Surgery.

Desmoplastic trichilemmoma, an uncommon variant of trichilemmoma, is a benign adnexal neoplasm originating from the outer root sheath of a hair follicle, which has rarely been associated with atypical basaloid proliferations, including basal cell carcinoma. In this patient case, a 67-year-old female presented to our dermatology clinic for a skin check. On physical examination, a pearly, pink papule was noted on the vertex scalp, and a biopsy was obtained to rule out malignancy. Histologic examination of the lesion favored a desmoplastic trichilemmoma; however, a basaloid neoplasm could not be ruled out. Subsequently, the patient underwent Mohs micrographic surgery, and upon examination of the Stage I Mohs slides, superficial basal cell carcinoma was identified within the lesion. This case serves to further strengthen the known association between basal cell carcinoma and desmoplastic trichilemmoma. In addition, it demonstrates that the presence of basal cell carcinoma may not be observed on the initial biopsy of these lesions, underscoring the utility of complete surgical excision.

Infiltrative Basal Cell Carcinoma (iBCC) Adjacent to a Desmoplastic Trichoepithelioma (DTE): A Case Report and Literature Review of iBCCs and DTEs.

The co-existence of an infiltrative basal cell carcinoma (iBCC) and a desmoplastic trichoepithelioma (DTE) within the same cutaneous lesion is a rare occurrence. iBCCs are relatively common malignant skin neoplasms that pose a risk for local tissue destruction and recurrence. DTEs are cutaneous neoplasms originating from hair follicles that may clinically and histologically appear similar to iBCCs but are ultimately benign. Distinguishing between these two entities is important given their differing destructive potential. Herein, we describe the case of a 36-year-old female with a single skin lesion on her left cheek that was comprised of both an iBCC distinct from a DTE, as verified by histopathologic analysis. A literature review highlights the rarity of such collision tumors and discusses the potential genetic links between these two histologically similar cutaneous neoplasms.

ISLET-1 expression in soft tissue neoplasms reveals high sensitivity but moderate specificity for desmoplastic small round cell tumors and potential utility as a diagnostic biomarker.

ISLET-1 (ISL1) is a LIM-homeodomain transcription factor. Selective ISL1 expression is shown in neuroendocrine, non-neuroendocrine, and some soft tissue tumors including desmoplastic small round cell tumor (DSRCT). We assessed the specificity of ISL1 (clone EP283, 1:500, Cell Marque) in 288 soft tissue tumors, which included 17 DSRCTs and other histologic mimics. Positive staining threshold for ISL1 was set to >10 % of neoplastic cell nuclei at moderate intensity. ISL1 IHC was positive in 15/16 (94 %) DSRCTs with 75 % showing diffuse (>50 %) expression. ISL1 was positive in 1/10 (10 %) Ewing sarcomas (EWS), 7/13 (54 %) alveolar rhabdomyosarcoma (RMS), 14/22 (63 %) embryonal RMS, 7/14 (50 %) synovial sarcomas, 15/16 (93 %) neuroblastoma, 1/5 (20 %) Wilms tumor, 2/4 (50 %) olfactory neuroblastoma, and all 9 Merkel cell carcinomas. Other tumors, including all CIC::DUX4 sarcomas, were negative except 3/27 leiomyosarcomas, and 1 each of angiosarcoma, myxoid liposarcomas, inflammatory myofibroblastic tumor, malignant peripheral nerve sheath tumor, tenosynovial giant cell tumor, dedifferentiated LPS, and 1 ectomesenchymoma. In summary, among the soft tissue tumors tested, ISL1 is a highly sensitive but moderately specific marker for DSRCT and may be useful to distinguish from round cell mimics including EWS and CIC::DUX4 sarcomas. The oncogenic role of ISL1 in these tumors warrants further investigation.

Clinical Characteristics and Special Considerations in the Management of Rare Melanoma Subtypes.

Rare histologic subtypes of melanoma, including acral, mucosal, uveal, and desmoplastic melanomas, only make up 5% of all diagnosed melanomas and are often underrepresented in large, randomized trials. Recent advancements in systemic therapy have shown marked improvement in pathologic response rates, improving progression-free and overall survival among cutaneous melanoma patients, but there are limited data to demonstrate improved survival among rarer subtypes of melanoma. Acral melanoma has a poor response to immunotherapy and is associated with worse survival. Mucosal melanoma has a large variability in its presentation, a poor prognosis, and a low mutational burden. Uveal melanoma is associated with a high rate of liver metastasis; recent adoption of infusion and perfusion therapies has demonstrated improved survival among these patients. Desmoplastic melanoma, a high-risk cutaneous melanoma, is associated with high locoregional recurrence rates and mutational burden, suggesting this melanoma may have enhanced response to immunotherapy. While these variants of melanoma represent distinct disease entities, this review highlights the clinicopathologic characteristics and treatment recommendations for each of these rare melanomas and highlights the utility of modern therapies for each of them.

Massive Desmoplastic Fibroma of the Proximal Tibia: Case Report.

Desmoplastic fibroma of bone is a very uncommon, benign but locally aggressive fibrogenic tumor. This report describes the case of a 45-year-old patient with a massive desmoplastic fibroma of the proximal tibia. A two-staged surgical procedure was successfully performed: wide resection and endoprosthetic reconstruction. Surgeons should be aware of the complexity of its treatment in the locally advanced and aggressive cases. A comprehensive review of the literature is also provided.

Prognostic factors based on histological categorization of desmoplastic reactions in pancreatic cancer.

BACKGROUND/PURPOSE: In colorectal cancer, the morphological categorization of fibrotic cancer stroma in the invasive frontal zone of the primary tumor is well reflected in the prognosis. Conversely, the histological characteristics of pancreatic cancer (PC) reveal fibrotic hyperplasia of stroma known as desmoplasia; however, its characterization is unknown. Therefore, this study aimed to evaluate the prognostic factors according to the histological categorization of desmoplastic reactions in PC. METHODS: We retrospectively enrolled 167 patients who underwent curative resection for PC. The desmoplastic pattern was histologically classified as mature, intermediate, or immature. Clinicopathological features were evaluated, and disease-free and overall survival (OS) were analyzed in the three groups. Prognostic factors were assessed using univariate and multivariate analyses. RESULTS: In total, 19 mature, 87 intermediate, and 61 immature desmoplastic patterns were evaluated. Jaundice decompression, white blood cell count, and platelet/lymphocyte ratio were significantly different among the groups. The mature group had a better disease-free survival (DFS) prognosis than the other two groups; however, OS did not differ between the groups. Desmoplastic patterns showed significant differences between the three groups for DFS. CONCLUSIONS: Desmoplastic patterns are a prognostic factor of DFS for PC, with mature desmoplastic reactions associated with good prognosis. Thus, they may aid in individualized therapeutic approaches in patients with PC.

Randomized Trial of Postoperative Radiation Therapy After Wide Excision of Neurotropic Melanoma of the Head and Neck (RTN2 Trial 01.09).

BACKGROUND: Cutaneous neurotropic melanoma (NM) of the head and neck (H&N) is prone to local relapse, possibly due to difficulties widely excising the tumor. This trial assessed radiation therapy (RT) to the primary site after local excision. METHODS: Participants from 15 international centers were randomized to observation or RT. The participants were required to have microscopically negative excision margins 5 mm wide or wider and no evidence of disease elsewhere. The primary outcome was time to local relapse. The secondary outcomes included time to any recurrence, overall survival (OS), and toxicity. RESULTS: The trial ceased prematurely due to slow recruitment and the COVID-19 pandemic. During 2009-2020, 50 participants were randomized: 23 to observation and 27 to RT. The most common NM subsites were scalp (32%), midface (22%), and lip (20%). The median depth of invasion was 5 mm, and desmoplasia observed in 69%. The median duration from randomization to last contact was 4.8 years. Four participants (8%) experienced local relapse as a first recurrence during the study period: 3 in the observation arm and 1 in the RT arm (hazard ratio [HR] 0.29; 95% confidence interval [CI] 0.03-2.76; p = 0.279). No statistically significant difference in time to any relapse or OS was observed. More than 6 months after randomization, grade 3 or greater toxicity was experienced by 10% of the participants in the observation arm and 12.5% of the participants in the RT arm of the study. CONCLUSION: Due to low accrual, the role of adjuvant RT for cutaneous NM of the H&N excised with microscopically negative margins 5 mm wide or wider remains undefined. Its routine use cannot be recommended. Local relapse might be less common than previously anticipated based on retrospective reports.

Diagnostic and prognostic significance of keloid-like collagen remodeling patterns in the extracellular matrix of colorectal cancer.

Background: The desmoplastic reaction is considered a promising prognostic parameter for colorectal cancer. However, intermediate desmoplastic reaction is characterized by sizeable stromal heterogeneity, including both small amounts of keloid-like collagen (KC) in the fibrotic stroma and thick tufts of KC circumferentially surrounding cancer nests and occupying most of the fields of view. The present study aimed to evaluate the diagnostic and prognostic significance of KC histophenotyping with a quantitative visual assessment of its presence in the stroma of the invasive margin of TNM (The "tumor-node-metastasis" classification) stage II/III colorectal cancer (CRC). Methods and results: 175 resected tumors from patients with TNM stage II/III CRC were examined. Keloid-like collagen was assessed according to Ueno H. criteria. KC was assessed at the primary tumor invasive margin using Hematoxylin & Eosin and Masson's trichrome staining. The cut-off point for KC was examined using "the best cutoff approach by log-rank test." Using a cutoff point of 30%, we histologically divided fibrous stroma in the invasive area into two groups: "type A"-KC ≤ 0.3 and "type B"-KC>0.3. Type A stroma was observed in 48% of patients, type B-in 52%. The association between collagen amount and 5-year recurrence-free survival (5-RFS) was assessed using Cox regression analysis. Kaplan-Meier analysis and log-rank tests were used to assess the significance of survival analysis. Analysis of categorical variables showed that increased KC in CRC stroma predicted adverse outcomes for 5-RFS (hazard ratio [HR] = 3.143, 95%, confidence interval [CI] = 1.643-6.012, p = 0.001). Moreover, in Kaplan-Meier analysis, the log-rank test showed that type B exhibited worse 5-RFS than type A (p = 0.000). Conclusion: KC is an independent predictor of 5-year overall and RFS in patients with TNM stage II/III CRC treated with surgery, with worse survival rates when the amount of KC increases by >30%.

Periocular Desmoplastic Malignant Melanoma and Orbital Invasion With Uncontrollable Disease: A Case Report.

Primary orbital melanoma and metastatic cutaneous melanoma of the orbit are extremely rare. Desmoplastic melanoma (DM) is an infrequent variant of melanoma that can extend from a superficial location into deep tissues by neurotropic mechanisms. A 78-year-old male was referred to us with a periocular mixed malignant melanoma (spindle cell melanoma with desmoplastic reaction) in his left lower eyelid with uncontrollable disease (orbital and inferior orbital rim invasion) despite treatment. The surgical technique consisted of an extended orbital exenteration, maxillectomy, and ethmoidectomy, with a 2 cm macroscopic surgical margin. We performed a delayed socket reconstruction with a temporalis muscle flap using a transorbital approach. The patient remained disease-free for 1.5 years with a good quality of life since exenteration surgery. At this time, he presented a recurrence in the area of the malar scar with a new orbital invasion, and finally, he died due to mediastinal, pleural, and pulmonary metastasis. The treatment of a cutaneous melanoma arising in the periocular region is a challenging reconstructive problem and it may compromise the globe and visual function.

Joinpoint regression analysis of recent trends in desmoplastic malignant melanoma incidence and mortality: 15-year multicentre retrospective study.

BACKGROUND: Recent data reveal a marked rise in the detection and mortality rates of Desmoplastic Malignant Melanoma (DMM). This trend underscores the imperative for an in-depth analysis of DMM's epidemiology, which is crucial for the formulation of precise medical and public health strategies. This investigation seeks to elucidate the variations in the incidence and mortality of DMM over a 15-year period (2005-2019). METHODS: Data on DMM patients was sourced from the Surveillance, Epidemiology, and End Results (SEER) database. Both incidence and incidence-based mortality rates (IBM) were directly extracted from the SEER database. Joinpoint regression was used to analyze and calculate the average annual percent change (AAPC) and its 95% confidence interval (CI). RESULTS: Between 2005 and 2019, 3,384 DMM cases were identified, boasting an age-adjusted incidence rate of 36.3 cases per 1000,000 person-years (95% CI 3.51-3.76) and an IBM of 1.65cases per 1000,000 person-years (95% CI 1.57-1.74). Of these, 2,353 were males (69.53%) and 1,031 were females (30.47%). There were 1894 patients (55.97%) who were over 70 years old. Predominantly, DMM lesions manifested in exposed areas: Limbs (955, 28.22%), Face (906, 26.77%), and Scalp and Neck (865, 25.56%). The incidence of DMM increased significantly at a rate of APC = 0.9% during 2005-2019, while the incidence-based mortality showed a significant upward trend (APC = 7%) during 2005-2012, and slowly increasing trend (APC = 0.6%) during 2012-2019. In contrast to the modest upward trajectory in female incidence and mortality, male incidence initially surged, later declining, while male mortality peaked and stabilized post-2012. The primary sites for incidence and mortality were chronically sun-exposed areas: Face, Scalp and Neck, and Limbs. CONCLUSIONS: In recent years, the incidence and incidence-based mortality of DMM have significantly increased. Each subgroup analysis has different trends, and these trends can provide better support for our exploration of DMM.

Single-cell multiomics profiling reveals heterogeneous transcriptional programs and microenvironment in DSRCTs.

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive sarcoma driven by the EWSR1::WT1 chimeric transcription factor. Despite this unique oncogenic driver, DSRCT displays a polyphenotypic differentiation of unknown causality. Using single-cell multi-omics on 12 samples from five patients, we find that DSRCT tumor cells cluster into consistent subpopulations with partially overlapping lineage- and metabolism-related transcriptional programs. In vitro modeling shows that high EWSR1::WT1 DNA-binding activity associates with most lineage-related states, in contrast to glycolytic and profibrotic states. Single-cell chromatin accessibility analysis suggests that EWSR1::WT1 binding site variability may drive distinct lineage-related transcriptional programs, supporting some level of cell-intrinsic plasticity. Spatial transcriptomics reveals that glycolytic and profibrotic states specifically localize within hypoxic niches at the periphery of tumor cell islets, suggesting an additional role of tumor cell-extrinsic microenvironmental cues. We finally identify a single-cell transcriptomics-derived epithelial signature associated with improved patient survival, highlighting the clinical relevance of our findings.

Case report: Is severe toxicity the price to pay for high sensitivity to checkpoint inhibitors immunotherapy in desmoplastic melanoma?

Background: Desmoplastic melanoma (DM) is a rare subtype of melanoma characterized by high immunogenicity which makes it particularly suitable for immune checkpoint inhibitors (ICIs) treatment. Case presentation: We report the case of a 53-year-old man with metastatic DM successfully treated with the combination of anti-CTLA-4 and anti-PD-1 antibodies, who developed serious immune-related adverse events (irAEs). The primary tumor was characterized by absent PD-L1 expression and no-brisk lymphocytes infiltration. NGS showed absence of BRAF mutation, a high tumor mutational burden, and an UV-induced DNA damage signature. Metastatic lesions regressed rapidly after few cycles of ICIs until complete response, however the patient developed serious irAEs including hypothyroidism, adrenal deficiency, and acute interstitial nephritis which led to the definitive suspension of treatment. Currently, the patient has normal renal functionality and no disease relapse after 26 months from starting immunotherapy, and after 9 months from its definitive suspension. Conclusion: Efficacy and toxicity are two sides of the same coin of high sensitivity to ICIs in DM. For this reason, these patients should be closely monitored during ICIs therapy to promptly identify serious side effects and to correctly manage them.

The Importance of In Vivo Reflectance Confocal Microscopy in a Case of Desmoplastic Melanoma.

Desmoplastic melanoma accounts for 5% of all cases of melanoma, but its diagnosis can be difficult due to its frequent clinical presentation with amelanotic lesions. Histologically, spindled melanocytes surrounded by a collagenous stroma are observed. Compared with other types of melanoma, the desmoplastic types presents greater local aggression, and is more prone to local recurrence, but has a lower risk of lymph node metastasis. Early detection, accurate staging, and proper surgical management are the main factors associated with higher survival rates in melanoma patients. Reflectance confocal microscopy (RCM) has proven to be a valuable imaging tool in the diagnosis of skin neoplasms, being useful for orientating practitioners towards the diagnosis of melanoma and indicating the necessity of performing a diagnostic biopsy. We present the case of 52-year-old woman, who presented to the dermatology department with an irregular, dark-colored plaque in the right deltoid region. Dermoscopy showed asymmetry with an atypical network and some areas of regression. RCM revealed pagetoid cells in the upper epidermis, cell atypia, non-edged papillae, dermal inflammation, and nucleated cells in the dermis, which are highly suggestive of melanoma. A biopsy was also performed. A histopathology exam confirmed the diagnosis of superficially spreading melanoma with a desmoplastic component, and revealed a Breslow index of 0.9 mm, Clark level IV, an absence of mitoses, angiolymphatic invasion and regression, and complete excision. The CT and PET-CT scans were negative. A biopsy of the axillary sentinel lymph node was conducted, with a negative result obtained, establishing the IB stage of the disease. The patient will remain under follow-up to look for a recurrence or a new primary melanoma.

Imaging Diagnosis of Desmoplastic Small Round Cell Tumor: A Report of Two Cases.

Desmoplastic small round cell tumor (DSRCT) is a rare multifocal peritoneal sarcoma, typically found in adolescent and young adult males. Symptoms are nonspecific and vary depending on tumor involvement. Diagnosis is primarily histopathological, although imaging results can assist in the diagnostic process. Although not pathognomonic, certain radiologic findings can help narrow down potential diagnoses and sometimes suggest the condition, as seen in our cases. Treatment options are not well-established or effective, and despite employing various therapeutic approaches, the prognosis remains poor. We present two cases of boys aged 11 and 10 with a final diagnosis of DSRCT, emphasizing the imaging findings.

Desmoplastic fibroma of the pediatric cranium with CTNNB1 mutation: case report and literature review.

PURPOSE: Desmoplastic fibroma (DF) is an uncommon intermediate bone tumor rarely involving the skull with unidentified pathogenesis. We report the first case of pediatric temporoparietal cranial desmoplastic fibroma (DF) with a CTNNB1 gene mutation and review the previous literature. CASE PRESENTATION: A 3-year-old boy had a firm, painless mass on the right temporoparietal region for 22 months. The cranial CT scan showed isolated osteolytic destruction in the outer plate and diploe of the right temporoparietal bone. Gross total resection of the lesion and cranioplasty were performed. After that, a growing epidural hematoma was observed so another operation was performed to remove the artificial titanium plate. Postoperative pathology indicated a DF diagnosis and molecular pathology suggested a missense mutation in exon 3 of the CTNNB1 gene (c.100G > A,p.Gly34Arg). CONCLUSION: Pediatric cranial DF is rare and easy to be misdiagnosed before operation. For cranial DF, lesion resection can be performed and perioperative management should be strengthened. Mutations in the CTNNB1 gene might be one of the molecular pathologic features of DF.

Desmoplastic Small Round Cell Tumor Presenting as an Intra/Extracranial Mass.

Desmoplastic small round cell tumors (DSRCTs) are highly malignant tumors, with distinct reciprocal chromosome translocation (11;22)(p13;q12). Intracranial metastasis is a very rare complication of this tumor, with only a few cases reported in the literature. To our knowledge, this is the only case presenting an extracranial extension of intracranial metastasis of DSRCT. A 33-year-old man was diagnosed with DSRCT in the pelvic cavity. He presented with a scalp lump and right-sided weakness. A biopsy showed metastasis from DSRCT. Metastatic DSRCT to the brain is extremely rare. Surgical resection followed by adjuvant treatment, including chemotherapy and radiation, is indicated as it has a poor prognosis. Moreover, aggressive treatment is warranted to prevent progression and relapse.

Subcutaneous fibroblastoma resembling hemangioma: A case of benign tumor of the chest wall.

Key Clinical Message: Desmoplastic fibroma presents similar to other soft tissue tumors to such an extent that even a gold standard investigation can miss. Abstract: This is to report a mass in a 47-year-old male arising from the chest wall, which was first thought to be a hemangioma but was later diagnosed as a case of desmoplastic fibroblastoma with the help of a biopsy.