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Introduction: different variables have been associated with a worse prognosis of patients with osteosarcoma (OS), highlighting tumor size, location in the axial skeleton and the presence of metastases. The objective of this study is to analyze the prognostic impact of diagnostic delay in osteosarcoma in adults in the Mexican population in a center specialized in sarcomas., Material and Methods: retrospective cohort study from January 1, 2005, to December 31, 2016, 96 patients over 21 years of age with a diagnosis of osteosarcoma were analyzed., Results: the median time to diagnosis from the onset of symptoms was six months (range: 2-36). This variable was dichotomized by applying the operator-dependent curve (ROC) analysis and we determined a cut-off value greater than five months, with an area under the curve (AUC) = 0.93 [95% CI 0.86-0.97], sensitivity 93.2% and specificity 94.6%., Conclusion: time until diagnosis is a critical factor in the survival of adult patients with osteosarcoma, highlighting its influence on disease progression and the appearance of metastasis. The correlation between diagnostic delay and an unfavorable prognosis reinforces the need for rapid and efficient evaluation in suspected cases of osteosarcoma.

Introduction: reconstruction of large bone defects using modular knee arthroplasty (MKA) presents a significant challenge in terms of functionality. The objective of the present work was to identify the different prognostic factors associated with failure of MKA in cancer patients., Material and Methods: a retrospective cohort study was conducted, including patients with a diagnosis of musculoskeletal tumor in the distal femur or proximal tibia, who underwent MKA between January 1, 2010, and December 31, 2021., Results: 49 patients were included, of which 25 (51.02%) were women and 24 (48.98%) men, with a mean age of 29.57 years. Of these, 14 (28.57%) patients experienced some type of MKA failure. The most frequent complication that led to failure was periprosthetic infection, observed in seven (14.29%) patients. Variables associated with MKA failure included biopsies performed outside our hospital (HR 3.2, 95% CI 1.4-6.4, p = 0.02), the length of the long axis of the tumor (HR 2.1, 95% CI 1.2-4.6, p = 0.01) and a prolonged surgical time (HR 3.37, 95% CI 1.1-8.6, p = 0.04)., Conclusion: the most significant prognostic factors associated with MKA failure in our cohort were tumor size, prolonged surgical time, and performance of the diagnostic biopsy in a center not specialized in the management of this type of patient. These findings highlight the importance of considering these variables to improve outcomes in patients undergoing MKA.

Background: Soft tissue sarcomas (STS) are a heterogeneous group of rare tumours that represent less than 1% of all malignant, solid tumours in adults. There is limited epidemiological information regarding STS in Latin America. Therefore, the objective of this study is to present an epidemiological profile of these tumours observed at a single reference centre., Methods: A retrospective study was carried out based on hospital records obtained from a registry of 879 patients with STS of the extremities who were treated at the National Cancer Institute of Mexico from January 1, 1994 to December 31, 2017. Epidemiological variables and relevant clinical data were collected. Five-year survival rates were analysed using Kaplan-Meier estimates, and a multivariate Cox proportional-hazards model measured associations., Results: A total of 879 records were collected. The median age was 45 years (15-95 years), and the ratio of men to women was 1:1, with 433 men (49.3%), and 446 women (50.7%). The median tumour size was 11.4 cm (2-49 cm). The most prevalent histological variants were liposarcomas and synovial sarcomas. The lower limb was the most frequently affected extremity, with the thigh being the most common site followed by the leg. A majority of the patients were diagnosed at clinical stages IIIA-IV., Conclusions: The data collected from the present cohort provides an overview of the epidemiological profile of STS at a single reference centre in Latin America, and allow comparison with global data., Competing Interests: The authors declare that they have no conflict of interest., (© 2021 Professor P K Surendran Memorial Education Foundation. Published by Elsevier B.V. All rights reserved.)

Introduction: Lymph node metastasis (LNM) in soft tissue sarcomas (STS) are uncommon, occurring in only 3% - 5% of all sarcomas, and are classified as Stage IV, along with distant metastasis (DM). This paper compares the prognosis of patients with lymphatic and DM, in extremity STS (eSTS)., Methods: A retrospective study was carried out in a high-volume sarcoma center; 853 patients with eSTS sarcomas were identified and classified from January 1, 1997 to December 31, 2017. Cases with pathological confirmation of LNM were included. Five-year survival rates were analyzed using the Kaplan-Meier method and the Cox proportional hazards model., Results: LNM was present in 46 of the cases (5.4%), with an overall survival of 21 months (95% confidence interval [CI], 16.7 - 25.2), compared to 18 months (95% confidence interval [CI], 14.2 - 21.7) in those with only DM. Median recurrence-free survival was 21 months (95% confidence interval [CI], 19.7 - 22.4), vs. 20 months (95% confidence interval [CI], 16.2- 23.7), respectively. LNM only and DM only had also a similar OS of 21 months (95% CI 16.7-25.2) vs 18 months (95% CI 14.2-21.7. N1M1 cases had the worse median OS with 15 months (95% confidence interval [CI], 10.9-19.7) CONCLUSIONS: Overall survival and recurrence free survival in patients with lymph node disease and metastatic disease are similar. However prognosis is worse in N1M1. Use of systemic treatment in patients with LNM is not as common as in metastatic cases, this difference in treatment and the fact that prognosis is similar suggests that both biological behavior and effect of treatment have been underestimated. A subclassification of clinical stage IV might be the next step., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Desmoid tumors represent a rare entity of monoclonal origin characterized by locally aggressive behavior and inability to metastasize. Most cases present in a sporadic pattern and are characterized by a mutation in the CTNNB1 gene; while 5-15% show a hereditary pattern associated with APC gene mutation, both resulting in abnormal β-catenin accumulation within the cell. The most common sites of presentation are the extremities and the thoracic wall, whereas FAP associated cases present intra-abdominally or in the abdominal wall. Histopathological diagnosis is mandatory, and evaluation is guided with imaging studies ranging from ultrasound, computed tomography or magnetic resonance. Current approaches advocate for an initial active surveillance period due to the stabilization and even regression capacity of desmoid tumors. For progressive, symptomatic, or disabling cases, systemic treatment, radiotherapy or surgery may be used. This is a narrative review of this uncommon disease; we present current knowledge about molecular pathogenesis, diagnosis and treatment.

Maffucci syndrome is characterized by the presence of multiple enchondromes and hemangiomas that can affect soft tissues and other organs. The risk of malignant transformation of lesions is 100% during the life of the individual, with chondrosarcoma being the most frequently associated malignant tumor. We present the case of a 44-year-old man diagnosed with Maffucci syndrome who developed a synchronous double primary: chondrosarcoma and high-grade multicenter fusocellular sarcoma of scapular and tricipital region, was treated with disarticulation interscapule-thoracic, presented accelerated progression and lung disease. There are other neoplasms associated with Maffucci syndrome, such as pancreatic adenocarcinoma, mesenchymal ovarian tumors, gliomas, astrocytomas and pituitary tumors. It is therefore very interesting to report the uncommon association between fusocellular sarcoma and secondary chondrosarcoma in patients with Maffucci syndrome. Follow-up in this group of patients is complex and is based on the intentional search for accelerated growing lesions, paying attention to progressive growth injuries, clinical symptoms or radiological malignancy data.

Introduction: Primary sacral tumors are rare, treatment in most cases is surgical with or without adjuvant radiotherapy; oncology and functional results are usually adverse with a high rate of complications., Material and Methods: We conducted a retrospective, analytical and observational studies that includes 22 cases treated between 2000 and 2017, analyzed their characteristics demographic, the type of treatment received, and the oncological, functional results and the rate of complications were analized., Results: 22 patients were subjected to sacrectomy with posterior approah because of cordoma (13 patients), giant cell tumour (three patients) and other (six patients). Three total sacrectomies, 13 partial sacrectomies, two hemisacrectomies and four sacrectomies enlarged were performed. The mean surgical time was 229 minutes, with an average bleeding of 2,100 cm3, the average tumour size was 13.8 cm (6-30cm); 10 patients were presented with complications, eight by surgical site infection, one sacral hernia and one osteomyelitis. Overall survival was 44.4 months., Conclusions: Treatment of sacral tumors is complex, requires a multidisciplinary team; the oncological result is adequate when you get free margins of neoplasia, the functional results will be determined by the type of resection, and the rate of complications is high however is the best alternative healing in our hospital.

Purpose: The BRAF V600E mutation has been described in melanomas occurring in the Caucasian, European, and Asian populations. However, in the Mexican population, the status and clinical significance of BRAF mutation has not been researched on a large scale., Methods: Consecutive BRAF-tested Mexican patients with metastatic melanoma (n = 127) were analyzed for mutations in exon 15 of the BRAF gene in genomic DNA by real-time polymerase chain reaction technology for amplification and detection. The results were correlated with the clinical-pathologic features and the prognosis of the patients., Results: The frequency of somatic mutation V600E within the BRAF gene was 54.6% (43 of 127 patients). Nodular melanoma was the most prevalent subtype in our population, with BRAF mutations in 37.2% (16 of 55 patients). In contrast, superficial spread had a frequency of 18.6% BRAF mutation (eight of 24). Other clinicopathologic features were assessed to correlate with the mutation status., Conclusion: This study searched for the most prevalent BRAF V600E mutation type in melanoma in a heterogeneous population from Mexico. Nodular melanoma was found to be the most prevalent in metastatic presentation and the presence of BRAF V600E mutation, perhaps related to the mixed ancestry; in the north, ancestry is predominantly European and in the south, it is predominantly Asian. The outcomes of the mutation correlations were similar to those found in other populations.

Dedifferentiated parosteal osteosarcoma is a variant in which a high grade osteosarcoma coexists with a parosteal osteosarcoma. We report the case of a 20-year-old female patient who presented with six months of evolution of pain and functional limitation of the right forearm, with no apparent cause; radiographs were performed, observing a tumoral lesion in the diaphysis of the right ulna. Physical examination showed pain upon palpation in the diaphysis of the ulna and limitation of prone-supination. Axial computed tomography of the thorax revealed metastatic disease in the upper lobe of the left lung. An incisional biopsy was performed on the right ulna, with a report of dedifferentiated parosteal osteosarcoma. Therefore, the patient was managed with neoadjuvant chemotherapy with cisplatin and doxorubicin until completing three cycles. Surgical treatment consisted of intercalary resection of the diaphysis of the right ulna, plus reconstruction of the microvascularized autologous graft of the right fibular diaphysis and graft stabilization with 3.5 mm dynamic compression plate (DCP) and one-third tubular plate. In the same procedure, pulmonary metastasectomy was performed by thoracoscopy. Post-surgical histopathological report with 100% necrosis. Currently, the patient is asymptomatic, with no evidence of tumor activity. Dedifferentiated parosteal osteosarcoma is a rare pathology, but should be suspected as a differential diagnosis in the presence of a parosteal osteosarcoma; it should be taken into account that this disease can metastasize due to its dedifferentiated pattern. It is important to plan a surgical treatment that allows an adequate functional reconstruction, always taking into account the oncological principle.

Background: The aim of this study was to analyze the clinicopathologic features of melanoma in México as the demographics of melanoma are not well known in Mexican and Latin American people., Materials and Methods: A total of 1219 patients with cutaneous melanoma were analyzed through a retrospective database collected from a cancer referral institute, and the results were compared with developed countries., Results: Median age was 57 years, and 713 (58.5 %) were females. The most common melanoma subtype was acral lentiginous melanoma (ALM), which was observed in 538 (44.1 %) patients. Median Breslow thickness was 5.2 mm. Among 837 patients with complete data, the 5-year disease-specific survival (DSS) was 52.3 %. Factors associated with worse DSS on univariate analysis were Breslow thickness (p < 0.001), recurrence (p < 0.001), ulceration (p < 0.001), positive margin (p < 0.001), ALM (p = 0.001), and male sex (p = 0.001). Multivariate analysis demonstrated Breslow thickness [hazard ratio (HR) 1.45, 95 % confidence interval (CI) 1.27-1.65; p < 0.001], positive margin (HR 1.25, 95 % CI 1.03-1.57; p = 0.018), recurrence (HR 9.56, 95 % CI 6.89-9.87; p = 0.002), ALM (HR 8.07, 95 % CI 6.77-8.95; p = 0.004), and male sex (HR 1.33, 95 % CI 1.06-1.68; p = 0.013) as independent risk factors for DSS., Conclusion: Our patients had worse prognosis compared with data from the US Surveillance, Epidemiology, and End Results database. We found male sex and ALM as independent risk factors for worse survival, in addition to known risk factors.

Background: Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma that affects elderly patients and typically arises in sun-exposed skin. The disease is very rare and only few cases present with no apparent skin lesion. In the retroperitoneum there are only two cases reported in the literature., Case Presentation: We report a case of a 54-year-old Mexican male with MCC, which presented as a large retroperitoneal mass. Pathological and immunohistochemical analysis of the transabdominal CT-guided biopsy specimen revealed a MCC. The patient underwent preoperative chemotherapy followed by a laparotomy and the mass was successfully excised., Discussion: There are two possible explanations for what occurred in our patient. The most plausible theory is the retroperitoneal mass could be a massively enlarged lymph node where precursor cells became neoplastic. This would be consistent with a presumptive diagnosis of primary nodal disease. Moreover, metastasis to the retroperitoneal lymph nodes has been reported as relatively common when compared to other sites such as liver, bone, brain and skin. The less probable theory is the non-described "regression" phenomena of a cutaneous MCC, but we are not found a primary skin lesion., Conclusion: Preoperative chemotherapy and excision of the primary tumor is the surgical treatment of choice for retroperitoneal MCC. We propose that further studies are needed to elucidate the true efficacy of chemotherapy in conventional and unconventional patients with MCC., (Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Osteosarcoma is the most frequent primary malignant bone tumor. It is characterized by osteoid production by tumor cells. Its most frequent location is in the metaphyses of long bones, but a purely diaphyseal presentation is reported in 10% of cases. We report the case of a female 25 year-old patient whose symptoms of pain and swelling of the right mid thigh started four months before, without an apparent cause. Femur X-rays showed a tumor in the femoral shaft. The MRI showed extension to soft tissues with no compromise of the neurovascular bundle. The histopathologic report of the incisional biopsy was osteoblastic and chondroblastic osteosarcoma, classified as Enneking IIB, AJCC IIB. Treatment consisted of three cycles of neoadjuvant chemotherapy. Then intercalary femur resection plus reconstruction with centromedullary nailing and a diaphyseal spacer were performed. The histopathologic report was 95% necrosis (Huvos grade III). Three cycles of adjuvant chemotherapy were given and now, 18 months after completing the latter, the patient has no signs of local or distant tumor activity, and she can walk unassisted. Despite the fact that osteosarcoma does not occur usually in the mid shaft of long bones, we should always bear it in mind as part of the differential diagnosis for other conditions that occur more frequently in that region. Such location allows for a broad gamut of surgical approaches that spare the adjacent joints.