Soft tissue sarcomas of the head and neck. Clinical and pathological evaluation of 108 cases in Mexico

BACKGROUND

Sarcomas constitute 1% of all malignancies, but 10% occur in the head and neck (HN), and they are poorly understood. We present a large series of Soft Tissue HN sarcomas in Mexican patients with survival analysis.

STUDY DESIGN

This is a retrospective study of cases in a cancer hospital.

METHODS

Review of files and pathology material. Literature review.

RESULTS

We analysed 108 patients (55 men / 53 women). The age at presentation was 37 years. The original diagnosis changed in nine cases (8.3%). The most common subtype was rhabdomyosarcoma. Ninety percent of tumours were deep, 91% were high grade, 44% had metastasis, 63% measured >5 cm, overall 5-year survival (5 y-OS) was 48%, and histological high grade was associated with poor survival (p = 0.026).

CONCLUSION

Sarcomas of the HN are rare. The most affected sites were paranasal sinuses. The majority of tumours were deep, > 5 cm and high grade, 50% had metastasis, the 5 y-OS was 48% and the only independent factor associated with 5 y-OS was histologic grade.

Extramural perineural invasion in pT3 and pT4 rectal adenocarcinoma as prognostic factor after preoperative chemoradiotherapy

Perineural invasion (PNI) is widely studied in malignant tumors, and its prognostic significance is well demonstrated in the head and neck and prostate carcinomas, but its significance in rectal cancer is controversial. Most studies have focused on evaluating mural PNI (mPNI); however, extramural PNI (ePNI) may influence the prognosis after rectal cancer resection. We evaluated the prognostic value of ePNI compared with mPNI and with non-PNI, in rectal resections after preoperative chemoradiotherapy in 148 patients with pT3 and pT4 rectal carcinomas. PNI was identified in 35 patients (23.6%), 60% of which were in the mPNI group. Factors associated with PNI were tumor invasion depth, lymph node metastasis, lymphovascular invasion, and venous invasion; patients with PNI were more likely to have positive resection margins (65.7% versus 11.6%). ePNI, compared with mPNI, was associated with female sex (64.3% versus 28.6%), positive surgical margins (42.8% versus 28.6%), recurrence (50% versus 28.6%), and death (92.9% versus 28.6%). The 5-year disease-specific survival rate was 78.1% for patients without PNI, compared with 63.7% for the mPNI group and 26.4% for the ePNI group (P<.001). On multivariate analysis, the independent adverse prognostic factors were ePNI (odds ratio [OR], 22.17; 95% confidence interval [CI], 17.03-24.58; P<.001), overall recurrence (OR, 9.19; CI, 6.11-10.63; P=.002), clinical stage IV (OR, 8.56; CI, 6.34-9.47; P=.003), and positive surgical margin (OR, 3.95; CI, 2.00-4.28; P=.047). In conclusion, we demonstrated the prognostic effect of ePNI for disease-specific survival in surgically resected pT3-pT4 rectal cancer patients with preoperative chemoradiotherapy.

Dominantly inherited micro-satellite instable cancer - the four Lynch syndromes - an EHTG, PLSD position statement

The recognition of dominantly inherited micro-satellite instable (MSI) cancers caused by pathogenic variants in one of the four mismatch repair (MMR) genes MSH2, MLH1, MSH6 and PMS2 has modified our understanding of carcinogenesis. Inherited loss of function variants in each of these MMR genes cause four dominantly inherited cancer syndromes with different penetrance and expressivities: the four Lynch syndromes. No person has an "average sex "or a pathogenic variant in an "average Lynch syndrome gene" and results that are not stratified by gene and sex will be valid for no one. Carcinogenesis may be a linear process from increased cellular division to localized cancer to metastasis. In addition, in the Lynch syndromes (LS) we now recognize a dynamic balance between two stochastic processes: MSI producing abnormal cells, and the host's adaptive immune system's ability to remove them. The latter may explain why colonoscopy surveillance does not reduce the incidence of colorectal cancer in LS, while it may improve the prognosis. Most early onset colon, endometrial and ovarian cancers in LS are now cured and most cancer related deaths are after subsequent cancers in other organs. Aspirin reduces the incidence of colorectal and other cancers in LS. Immunotherapy increases the host immune system's capability to destroy MSI cancers. Colonoscopy surveillance, aspirin prevention and immunotherapy represent major steps forward in personalized precision medicine to prevent and cure inherited MSI cancer.

A high body mass index is not a worse prognostic factor for endometrial carcinoma in a predominantly obese population

AIM

We investigate if body mass index (BMI, kg × m(2)) is related to clinical-pathological characteristics in primary tumor and disease outcome in endometrial cancer.

BACKGROUND

Endometrial cancer incidence is increasing in industrialized countries. High BMI is associated with worse prognosis for many diseases.

INTRODUCTION

Endometrial carcinoma is the most common gynecological malignancy in industrialized countries and the incidence has been increasing over the last few decades associated with obesity, however, it is not clear if a high BMI is associated with poor prognosis.

PATIENTS AND METHODS

In total, 147 women primarily treated for endometrial carcinoma at the Instituto Nacional de Cancerología during 2000-2005 were studied. Body mass index was available for all patients and related to comprehensive clinical and histopathological data.

RESULTS

High BMI was related to endometrioid histology and low/intermediate grade, and overweight/obese women had the same survival as the normal/underweight women. In survival analysis adjusting for age, histological subtype and grade, BMI showed no independent prognostic impact.

CONCLUSION

High BMI was significantly associated with markers of non-aggressive disease and women with high BMI had the same survival time in univariate analysis.

Atypical small acinar proliferation: utility of additional sections and immunohistochemical analysis of prostatic needle biopsies

BACKGROUND

In surgical pathology, atypical small acinar proliferation is commonly detected in prostate biopsies. Most studies on atypical small acinar proliferation have examined morphological characteristics and the utility of immunohistochemical studies. However, these resources are not available to many pathology departments. We have found that examining additional sections is a simple and inexpensive method that allows better evaluation of focal prostatic glandular atypia.

OBJECTIVES

The present report compares the diagnostic utility of immunohistochemical techniques versus examining additional sections in prostate biopsies with focal glandular atypia.

PATIENTS AND METHODS

Thirty recently studied prostate biopsies with focal glandular atypia were selected. In each case, 3 additional levels were examined. An immunohistochemical study was performed on one level using an antibody against high-molecular-weight keratin (34BetaE12). Two additional sections were stained with hematoxylin and eosin.

RESULTS

The diagnosis of focal carcinoma was established with only additional sections in 4 cases (13.3%). In 2 of these biopsies, additional areas of carcinoma were found that were not identified in the original sections. In 4 other cases, immunohistochemical analysis was the only useful method for diagnosing cancer. In 9 cases (30%), both methods were useful for classifying focal glandular atypia as carcinoma. In the remaining 13 cases,neither immunohistochemical analysis nor additional sections were useful in changing the diagnosis of focal glandular atypia.

CONCLUSIONS

Focal glandular atypia in prostatic needle biopsies should be routinely examined with additional sections, particularly when immunohistochemical analysis is not possible. Some biopsies with atypical glandular proliferation may show focal carcinoma in additional sections, even if the immunohistochemical analysis did not provide a diagnosis of malignancy. Additional sections can also reveal areas of carcinoma that were not apparent in the original sections.

Gastric cancer in Latin America

Every year, cancer affects more than one million Latin Americans. The increasing incidence of cancer could be secondary to an aging population, westernization of life style, and urbanization. LA has among the highest incidence rates of gastric cancer, compared to other countries. In this review, different studies on gastric cancer and its relation with risks factors, such as infections, diet and life styles typical of LA, besides the different molecular alterations of that specific population (mainly at a genetic polymorphism level) are analyzed. An exhaustive research was made in PubMed, MEDLINE and Embase of the most relevant studies conducted in the last 27 years (1990-2017) in LA.

Frequency of Defective Mismatch Repair System in a Series of Consecutive Cases of Colorectal Cancer in a National Cancer Center

BACKGROUND

The frequency of colorectal cancer (CRC) with defective mismatch repair (dMMR) is estimated between 5 and 15%. In our population, the frequency of dMMR is unknown. Our objective was to show the frequency of dMMR.

METHODS

Determination of dMMR with immunohistochemistry was performed prospectively for 202 patients who presented consecutively with CRC for the first time at our institution.

RESULTS

The median age was 59 years (IQR 47 to 68), 119 (58.9%) were women, and 43 (21.3%) cases showed dMMR. The only clinicopathological characteristics associated with dMMR were the location in the right colon and the presence of a family history of cancer. In the multivariate analysis, only the presence of the tumor in the right colon was associated with dMMR (OR = 5.823, 95%-C.I. = 2.653-12.784, p < .001).

CONCLUSION

The 21.3% of the cases demonstrated a dMMR and the only clinical-pathological characteristic associated with dMMR was location in the right colon.

Epidemiological profile of soft tissue sarcomas of the extremities: Incidence, histological subtypes, and primary sites

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.

Ovarian carcinoma: pathology review with an emphasis in their molecular characteristics

Ovarian carcinoma is highly aggressive and difficult to treat neoplasm, which is usually detected in advanced stages where most patients recur. Extensive investigation about several treatment modalities has been performed but this neoplasm has poor benefits from such treatments including targeted therapy. Recent data have begun to highlight the histological and molecular heterogeneity of these tumors defining this neoplasm, not as a single disease but a group of heterogeneous histological subtypes with important differences in terms of genetics, morphology, oncogenesis, prognosis, chemosensitivity and especially molecular characteristics that are likely to be targets of new molecules. In general, high-grade serous carcinomas are characterized by great genomic instability and frequent amplifications and deletions; lowgrade ovarian neoplasms are genomically stable. On this phytopathogenic basis, recent findings suggest a dual model of carcinogenesis consisting of two large groups named types I and II. Type I cancers (serous, mucinous, and low-grade endometrioid) commonly arise from well-described, genetically stable precursor lesions (usually borderline tumors); manifests as large adnexal masses with the early-stage disease, and they have a good overall prognosis. In contrast, type II carcinomas (serous, high-grade endometrioid, mixed, and undifferentiated carcinomas) originate de novo from the adnexal epithelium, often demonstrate chromosomal instability, and have aggressive biological behavior. Surprisingly, most of the genomic abnormalities detected encode known oncogenic proteins for which there is targeted therapy. Then, there is a real potential for personalized medicine adapted to the molecular portrait of tumors. In this review, I synthesize the histology and molecular pathology of ovarian carcinomas and possible strategies to reach targeted therapy.

Reclassification of lesions in biopsies by fine-needle aspiration of pancreas and biliary tree using Papanicolaou classification

BACKGROUND

Our aim was to evaluate the application of the classification of the Papanicolaou Cytopathology Society for the report of biopsies by fine-needle aspiration (FNA) of pancreas and bile duct.

METHODS

The FNAs obtained consecutively during 1 year were analyzed. Descriptive statistics were performed and sensitivity, specificity, positive predictive value, negative predictive value, and cytohistological correlation were determined. The reference standard test was the histopathological study.

RESULTS

A total of 134 cases of FNA were reclassified with ultrasound guidance according to the classification of the Papanicolaou Society, the median age was 59 years (range, 25-80 years). A case interpreted as non-diagnostic was reclassified to category 4 and 3 cases with atypical cells were reclassified to category 5. All malignant cases remained unchanged. Surgical follow-up was performed in 35 patients (26.1%), with a cytohistological concordance in 21 cases (91.3%) and 2 discordant cases (8.7%), the reasons for the discrepancy were due to sampling error, one of them with scarce material to make a diagnosis of higher category, the other case with partial agreement, because cytology was observed atypical cylindrical epithelium, with histology of grade 2 neuroendocrine neoplasia and low grade mucinous intraepithelial neoplasia. In general, the sensitivity and specificity were 100% and 75% respectively, the positive predictive value 88% and the negative predictive value 100%.

CONCLUSIONS

The FNA guided with endoscopic ultrasound (EUS) and interpreted according to the Papanicolaou Cytopathology Society Classification is an accurate method to evaluate pancreatic and biliary tract lesions with a high positive predictive value of 88%.

Association of ki67 Index with Recurrence in Gastrointestinal Stromal Tumors

PURPOSE

Gastrointestinal stromal tumors (GIST) have the potential to recur and metastasize. Several prognostic schemes have been developed but none are precise enough and most times the pathologist faces a small biopsy where it is not possible to evaluate the mitotic count. Our aim was to determine the influence of ki67 index and other clinicopathologic characteristics in the recurrence of GIST.

METHODS

Forty-three consecutive cases of GIST were studied. The cases presented with non-metastatic disease. We compared the clinicopathologic features of cases with recurrence against those with non-recurrence. The ki67 index was determined by square-millimeters.

RESULTS

The median age was 55 years (IQR 45-63), the most frequent site of involvement was the stomach with 21 (48.8%) cases, and the median of tumor diameter was 10 cm (IQR 5.5-17.5). Twenty-six (60.5%) cases were spindle cell, 13 (30.2%) were mixed, and 4 (9.3%) were epithelioid. The median mitosis count for 50 high power fields was 4 (IQR 0-16), while per square millimeter it was 1 (IQR 0-5, range 0-32). The median of the ki67 proliferation index was 5% (IQR 1-20). During the period of study, 11 (25.6%) patients recurred. The only significant differences between patients with GIST with recurrence and without recurrence were the sex and tumor size.

CONCLUSION

We did not find an association of the ki67 index with recurrence. The factors associated with recurrence were a high tumor size (> 10 cm) and male sex.

Overall survival of patients with colon cancer and a prolonged time to surgery

BACKGROUND

Factors associated with the time to surgery (TTS) and survival in colon cancer (CC) have not been well studied. Our aim was to find if the TTS has changed in our institution over time and to determine if it influences the survival.

METHODS

Retrospective cross-section study of 266 CC analyzed between two periods, and according to the quartiles of TTS, we performed a survival analysis.

RESULTS

The median age was 57 years; there was no predominance of sex, and about half of the patients were in stage III. The median TTS was 38 days, and 75% of the cases were operated before 60 days. The median TTS for 2005 to 2010 was 36 days, while for 2011 to 2015 was 41 days (P = 0.107). The survival was not statistically different between cases (1) operated with a delayed TTS or not, (2) operated in four cut-off points of TTS, (3) two different periods of attention, and (4) according to the clinical stage.

CONCLUSION

We did not find an association between the TTS with low survival. TTS has increased in the last period so we must work to make the diagnostic process more efficient in our patients to meet international quality standards.

Mesorectal Invasion Depth in Rectal Carcinoma Is Associated With Low Survival

BACKGROUND

Most cases of rectal cancer (RC) in our institution are in pathologic stage T3. They are a heterogeneous group but have been classified in a single-stage category. We performed the present study to validate the prognostic significance of the mesorectal extension depth (MED) in T3 RC measured in millimeters beyond the muscularis propria plane.

MATERIALS AND METHODS

We performed a retrospective analysis of 104 patients with T3 RC who had undergone curative surgery after a course of preoperative chemoradiotherapy at a tertiary referral cancer hospital. The patients were grouped by MED (T3a, < 1 mm; T3b, 1-5 mm; T3c > 5-10 mm; and T3d > 10 mm). The clinicopathologic data and disease-free survival were analyzed.

RESULTS

The 5-year disease-free survival rate according to the T3 subclassification was 87.5% for those with T3a, 57.9% for T3b, 38.7% for T3c, and 40.3% for those with T3d tumors (P = .050). On univariate and multivariate analysis, the prognostic factors affecting survival were overall recurrence (hazard ratio [HR], 3.670; 95% confidence interval [CI], 1.710-7.837; P = .001), histologic grade (HR, 2.204; 95% CI, 1.156-4.199; P = .016), mesorectal invasion depth (HR, 1.885; 95% CI, 1.164-3.052; P = .010), and lymph node metastasis (HR, 1.211; 95% CI, 1.015-1.444; P = .033).

CONCLUSION

MED is a significant prognostic factor in patients with T3 RC who have undergone neoadjuvant chemoradiotherapy, especially when the MED is > 5 mm. The MED could be as important as other clinicopathologic factors in predicting disease-specific survival.

Conjunctival melanoma: survival analysis in twenty-two Mexican patients

PURPOSE

To describe the cases of conjunctival melanoma (CM) and report the disease-free interval (DFI) and overall survival (OS).

METHODS

The charts of 22 patients who were admitted to two hospitals between 1985 and 2006 were reviewed for pertinent data, including demographics, site of involvement in the conjunctiva and sub-sites, surgical treatment, and adjuvant treatment.

RESULTS

There were 10 (45.45%) males and 12 (54.55%) females. Mean age was 52.3 years. In this group, 15 patients (68.1%) involved the bulbar conjunctiva, and 7 (31.9%) involved the palpebral conjunctiva. Of the 22 patients, 72.72% had a history of conjunctival melanosis. The average tumor size was 20.4 mm. Eight (36.36%) patients underwent orbital exenteration, 2 (9.06%) had enucleation, 5 (22.72%) had wide excision of the lesion followed by radiotherapy, 2 (9.06%) had orbital exenteration with neck dissection, and the remaining 5 patients (22.72%) were considered adequately treated only with wide excision. Eight (36.36%) patients received adjuvant treatment. Disease-free survival at 5 years was 51% and the overall survival at 5 and 10 years was 50% and 37%, respectively.

CONCLUSION

Conjunctival melanoma is a rare entity. Tumor behavior is aggressive, and the optimal treatment is surgery with adjuvant therapy.

Gastrointestinal Stromal Tumors Risk of Recurrence Stratification by Tumor Volume is a Best Predictor Compared with Risk Based on Mitosis and Tumor Size

PURPOSE

Gastrointestinal stromal tumors (GIST) have the potential to recur and metastasize. Several prognostic schemes have been developed, mostly based on the mitotic count, diameter, and tumor site. However, these systems are not precise enough. The research question was whether the tumor size determined by volumetry allows a better risk stratification than the traditional system, and our aim was to determine the value of tumor volumetry, a feasible and simple parameter, in the recurrence of GIST.

METHODS

Seventy-four cases of GIST were studied. The cases presented with non-metastatic disease, which were resected and did not receive imatinib. We compared the clinico-pathologic features of the cases with recurrence against those with non-recurrence and compared the tumor volumetry against the classification system based on tumor size and mitosis.

RESULTS

The median age was 58 years (range: 25 to 91 years). Half of the cases were presented in the stomach. The tumor size had a median of 8 cm (range of 1-30 cm). The median mitosis count for 50 HPF was 4 (range 0-92). During the period of study, 16 (21.6%) patients suffered recurrence. The significant differences were that patients with recurrence accounted for more deaths and the follow-up period was larger. The area under the curve (AUC) of the volumetry classification was superior to the AUC of the classification system based on tumor size and mitosis (NIH-criteria) (p = .05).

CONCLUSION

Tumor volumetry calculated in the surgical specimen and/or pre-operative tomography was superior to the NIH consensus in stratifying the risk of recurrence in GIST.

Maxillary Sinus Sarcomas: Epidemiological and Clinicopathological Experience of 25 Years in a National Reference Cancer Center

The aim of this study was to report our experience with malignant soft tissue tumors of the maxillary sinus in the period between 1985 to 2010. This is a retrospective case study in a tertiary cancer center setting. Review of patient's records and new evaluation of pathological specimens were made for 20 patients (14 men and 6 women) still met present criteria. After review the most common histological diagnoses were malignant peripheral nerve sheath tumor and malignant fibrous histiocytoma. There are male sex predilection, the median age was 38.9 years; 95% of tumors were >5 cm, 80% were high grade, 0% have metastatic disease at the diagnosis and the tumors were initially treated by surgical resection had better survival (p = 0.02). We present the results of a one of the larger series published to date in maxillary sinus sarcomas where analyzed the clinicopathological characteristics of 20 cases.

Extramural Perineural Invasion in pT3 and pT4 Gastric Carcinomas

BACKGROUND

Perineural invasion (PNI) is widely studied in malignant tumors, and its prognostic significance is well demonstrated. Most studies have focused on evaluating the mural PNI (mPNI); however, extramural PNI (ePNI) may influence the prognosis in gastric cancer. We evaluated the prognostic value of ePNI compared with mPNI in gastric cancer in this observational comparative cross-sectional study.

METHODS

Seventy-three pT3 and pT4 gastric carcinomas with PNI were evaluated. Forty-eight (65.7%) were in the mPNI group and the remaining in the ePNI group.

RESULTS

Clinicopathologic characteristics between the two groups were similar, except for the outcomes. The 5-year disease-specific survival (DSS) rate was 64% for the mPNI group and 50% for the ePNI group (p=.039), a difference that did not remain significant in multivariate analysis. The only independent adverse prognostic factor in multivariate analysis was the presence of lymph node metastasis (hazard ratio, 1.757; 95% confidence interval, 1.082 to 2.854; p=.023).

CONCLUSIONS

We demonstrated the prognostic effect of ePNI for DSS in surgically resected pT3-pT4 gastric cancer patients. ePNI could be considered in the staging and prognostic systems of gastric cancer to stratify patients with a high risk of recurrence.

Comparison of 3 Ways of Dissecting the Pancreatoduodenectomy Specimen and Their Impact in the Lymph Node Count and the Lymph Node Metastatic Ratio

BACKGROUND

Lymph node metastasis (LNM) is a strong prognostic factor in the cancer of the pancreatobiliary tree, but it is influenced by the number of lymph nodes (LNs). The lymph node ratio (LNR) is considered a more reliable factor than the number of LNM. The aim was to examine the LN retrieval and the LNR of 3 pathologic work-up strategies.

METHODS

Pancreaticoduodenectomies (n = 165) were analyzed comparing 3 pathological dissection techniques, classified as "control," "Verbeke method," and "Adsay method" groups.

RESULTS

The mean of the dissected LNs and the number of cases with >20 LNs were superior in the Adsay method group, compared with the other groups ( P < .001). The LNR was different between the Adsay and Verbeke groups (0.144 vs 0.069, P = .032). The median of the 3 positive LNs was associated with decreased survival compared with an absence of LNM (3-year specific survival of 48% vs 22%, P = .011). In the multivariate analysis, LNM (hazard ratio = 6.148, 95% confidence interval = 2.02-8.1, P = .042) and the evaluation of >15 LNs (hazard ratio = 12.52, 95% confidence interval = 5.51-21.01, P = .001) were independent predictors of survival.

CONCLUSION

The Adsay technique for LN retrieval was associated with a better LN count, more cases with LNM, and an LNR >0.1.

Medullary colonic carcinoma with microsatellite instability has lower survival compared with conventional colonic adenocarcinoma with microsatellite instability

INTRODUCTION

Colorectal medullary carcinoma (MC) is a rare subtype of poorly differentiated adenocarcinoma (PDA) with unclear prognostic significance. Microsatellite instable (MSI) colorectal carcinomas have demonstrated better prognosis in clinical stage II.

AIM

To analyze the survival and clinicopathological characteristics of MCs versus PDAs with MSI in clinical stage III.

MATERIAL AND METHODS

We studied 22 cases of PDAs with MSI versus 10 MCs.

RESULTS

Of the 10 MCs, 7 patients were men; the mean age was 57.8 ±5.6 years. The mean tumor size was 9.6 ±4.1 cm, and the primary site was the right colon in 9; 7 patients showed lymph node metastases (LNM) and lymphovascular invasion (LVI). Of the 22 PDA cases, 12 (54.5%) were women with a mean age of 75 ±16.1 years. The mean tumor size was 6.4 ±3.2 cm. Twelve (54.5%) presented in the right colon, 21 (95.5%) showed LNM and 7 (31.8%) LVI. Follow-up was 32 ±8 months, with a 5-year overall survival of 42.9% for MCs and 76.6% for PDAs (p = 0.048). Univariate analysis found local recurrence (p = 0.001) and medullary subtype (p = 0.043) associated with lower survival.

CONCLUSIONS

Medullary carcinomas were of greater tumor size and associated with more LVI and worse survival versus PDAs with MSI in stage III.

BRAF Mutation (V600E) Prevalence in Mexican Patients Diagnosed with Melanoma

BACKGROUND

B-Raf is a serine/threonine protein kinase activating the MAP kinase/ERK-signaling pathway. It has been shown that 50% of melanomas harbor activating BRAF mutations, with over 90% being the V600E mutation.

OBJECTIVE

The goal of this research was to determine the prevalence of the BRAF V600E mutation in patients from Central Mexico diagnosed with primary melanoma.

METHODS

Skin biopsies from 47 patients with melanoma were obtained from the dermatology department of the Hospital General 'Dr. Manuel Gea González' in Mexico City. For BRAF mutation determination, after DNA isolation, the gene region where the mutation occurs was amplified by PCR. Subsequently, the presence or absence of the V600E mutation was detected by Sanger sequencing performed at the private molecular diagnostic laboratory Vitagénesis in Monterrey, Mexico.

RESULTS

Of the 47 patients sampled, 6.4% harbored the V600E mutation. No statistical significance was found between mutations and the type of tumor.

Oligodendroglial cell proliferation arising in an ovarian mature cystic teratoma. Clinicopathological, inmunohistochemical, and ultrastructural study of a case that may represent an oligodendroglioma

Ovarian mature cystic teratoma (OMCT) is an ovarian benign neoplasm with excellent prognosis presenting components of the three germinal layers. However, transformation into a malignant neoplasm is a rare event (so-called somatic transformation). In most of the cases, the malignant component expresses as epidermoid carcinoma, but occasionally central nervous system tumors occur. Some of the previously reported tumors are astrocytoma, glioblastoma, and ependymoma. Somatic transformation of OMCT into an oligodendroglioma is exceptional. We report a 19-year-old female with a left OMCT with an area of oligonedroglial cells proliferation characterized by immunohistochemical studies with positivity for GFAP and S100, with a low Ki67 index (5%). Additionally, electron microscopy revealed oligodendrocytes with parallel bundles of cytoplasmic intermediate filaments, confirming the oligodendroglial nature of the proliferation. The patient was treated only with left oophorectomy, and three and half years after surgery, there is no evidence of disease.

Importance of tumor size in soft tissue sarcomas: a proposal for a nomogram based on a score system to staging soft tissue sarcomas in the postoperative setting

In order to adequately stage patients with extremity soft tissue sarcomas (ESTS), it is mandatory to include all adverse prognostic factors and create an integral staging system. We were able to evaluate a nomogram based on a score (STSSS), to improve ESTS staging. We retrospectively evaluated 596 patients with ESTS in stages I-III, of the American Joint Committee on Cancer (AJCC), who had a complete resection. We analyzed the influence of clinicopathological factors on metastasis, recurrence, and disease-specific survival. The STSSS was based on histologic grade (HG), profundity, tumor size (TS), and surgical margins; we also compared STSSS versus AJCC systems in their ability to stage ESTS. The mean TS was 11.8 cm, with 50%>10 cm. Large TS and high HG were independent but adverse prognostic factors for metastasis. In addition, large TS, high grade, and R1 resection were independent adverse prognostic factors for decreased survival. There was a progressive decline in survival as TS increased, although AJCC staging did not correlate well between stages (IA vs. IB p=0.233, IA vs. IIA p=0.123, IA vs. IIB p=0.075, IB vs. IIA p=0.472, IB vs. IIB p=0.211). STSSS showed differences between these categories for 5-year survival (I vs. II p=0.003, II vs. III p=0.002, III vs. IV p<0.001). Surgical margins, HG, and TS are important determinants for metastases and survival. We also found a strong correlation between survival and prognosis with the use of STSSS in the immediate postoperative setting.

Colorectal lymphoma in Mexico: clinico-pathological and survival analysis

BACKGROUND

Primary colorectal lymphomas (PCLs) are very rare. We analyze a series of PCL to establish an approximate frequency of the disease and their clinico-pathological characteristics.

METHODS

A retrospective cross-sectional study in a third-level hospital from 2006-2016. Clinico-pathologic features of 18 cases are presented.

RESULTS

PCL corresponded to 1.5% of malignant colorectal neoplasms. Ten cases presented in men, the median age was 57 years, diffuse large B-cell lymphoma (DLBCL) was the most common subtype (55.6%), 55.6% presented in cecum, 83.4% as unique polypoid tumor and the median size was 52.5 mm. The most prevalent presentation symptom was abdominal pain (61.1%). Six cases (33%) received initial surgery followed by chemotherapy, 7 cases (39%) received only chemotherapy, 2 cases received only surgery and 3 cases no-treatment. The 2-year disease specific survival was 62.7%. The only factors associated with improved survival in univariate analysis were use of surgery followed by chemotherapy (P=0.043) and HIV (P=0.043). On multivariate analysis none factor was an independent risk factor for decreased survival.

CONCLUSIONS

The improved overall survival rates in our series emphasize the importance of surgery followed systemic therapy in the treatment of this disease.