Objective: To analyze the clinicopathological features and differential diagnosis of interdigitating dendritic cell sarcoma (IDCS). Methods: The clinical pathological features of 7 IDCS were analyzed. Among them, the follow-up results of 6 cases were available. Results: Among the 7 IDCS patients, 4 cases were male and 3 were female. The age of the patients ranged from 26 to 69 years.Three cases were originated from lymph nodes and 4 cases were originated from skin, stomach, adrenal gland and mesentery, respectively. Microscopically, the tumor cells presented as fascicular and storiform proliferation and infiltrated by lymphocytes. The tumor cells were short-spindle or ovoid, with indistinct border of cytoplasm. The immunohistochemistry results showed that tumor cells were S-100, Vim, CD68 and CD163 positive, and AE1/AE3, EMA, CD117, CD34, Desmin, SMA, CD1α, CD21, CD23, CD35, HMB45, Melan-A, MelanPan and ALK negative.The BRAF mutation and clonal rearrangement of T and B cells were not detected. Among the follow-up period of 7 IDCS patients, 3 occurred disease progressions. Conclusions IDCS is extremely rare with unique pathological features, and its lesion is not limited to the lymph node. The IDCS patients with extensive lesions may have worse prognose. The differential diagnosis of IDCS includes other histiocytic and dendritic cell neoplasms, malignant melanoma and soft tissue neoplasms.

Objective To analyze the clinicopathological features and differential diagnosis of interdigitating dendritic cell sarcoma (IDCS). Methods The clinical pathological features of 7 IDCS were analyzed. Among them, the follow?up results of 6 cases were available. Results Among the 7 IDCS patients, 4 cases were male and 3 were female. The age of the patients ranged from 26 to 69 years.Three cases were originated from lymph nodes and 4 cases were originated from skin, stomach, adrenal gland and mesentery, respectively. Microscopically, the tumor cells presented as fascicular and storiform proliferation and infiltrated by lymphocytes. The tumor cells were short?spindle or ovoid, with indistinct border of cytoplasm. The immunohistochemistry results showed that tumor cells were S?100, Vim, CD68 and CD163 positive, and AE1／AE3, EMA, CD117, CD34, Desmin, SMA, CD1α, CD21, CD23, CD35, HMB45, Melan?A, MelanPan and ALK negative.The BRAF mutation and clonal rearrangement of T and B cells were not detected. Among the follow?up period of 7 IDCS patients, 3 occurred disease progressions. Conclusions IDCS is extremely rare with unique pathological features, and its lesion is not limited to the lymph node. The IDCS patients with extensive lesions may have worse prognose. The differential diagnosis of IDCS includes other histiocytic and dendritic cell neoplasms, malignant melanoma and soft tissue neoplasms.

Objective To evaluate the safety and efficacy of surgical treatment after neoadjuvant chemotherapy (NCT) for patients with cT4N+colon cancer, and to explore whether the indication of NCT for colon cancer can be extended from cT4b to cT4N+. Methods The clinical data of 40 patients with cT4N+colon cancer who underwent neoadjuvant chemotherapy followed by surgical treatment was retrospectively analyzed. The safety of neoadjuvant chemotherapy, surgical complications, R0 resection rate, tumor regression grade and prognosis were evaluated. Results Of the 40 patients, 23 were male and 17 were female; the median age was 57 years old. All patients were well tolerated with chemotherapy, and only one case (1／40, 2.5%) had grade 3 chemotherapy?related adverse event. They all underwent surgery after chemotherapy, and 95.0%(38／40) achieved microscopically clear resection (R0). Of the 11 patients with cT4b, 54.5%( 6／11) had undergone multivisceral resection ( MVR). Postoperative pathological results showed that 12 patients had moderate to severe tumor regression, including one ( 1／40, 2.5%) achieved pathologic complete response (pCR).29(72.5%) and 22 (55.0%) patients achieved down?staging of tumor T stage and N stage, respectively. The occurrence of surgical complications was 22.5%(9／40), including one case of anastomotic leakage (1／40, 2.5%). The 3?year disease?free survival and overall survival of the whole group were 75.0% and 80.0%, respectively. Conclusion Surgery after neoadjuvant chemotherapy is safe and effective for patients with cT4N+colon cancer, therefore indications for neoadjuvant chemotherapy for advanced colon cancer can be extended to cT4N+ stage.

Objective:To explore the clinicopathological and prognostic features of young onset patients with middle-low rectal cancer who received neoadjuvant chemoradiotherapy (NCRT).Methods:After NCRT, a total of 441 patients with primary middle-low rectal cancer treated with radical surgery at the Cancer Hospital, Chinese Academy of Medical Sciences (CHCAMS) from January 2004 to December 2016 were included. According to the age of disease onset, the patients were divided into the young group (51cases) and the middle-old group (390 cases), and the clinicopathological characteristics and survival of these patients were analyzed.Results:In the young group, 68.6% of patients received radical surgery within 7 weeks after NCRT, which was higher than 52.8% in the middle-old group ( P=0.047). The stage ypTNM Ⅲ in the young group was 51.0%, higher than 34.1% in the middle-old group ( P=0.027). The stage ypN+ in the young group was 51.0%, higher than 34.1% in the middle-old group ( P=0.047), The incidence of disease progression in the young group was 39.2%, higher than 25.1% in the middle-old group ( P=0.049). The incidence of distant metastasis in the young group was 35.3%, higher than 21.5% in the middle-old group( P=0.044). Most cases of disease progression occurred in the first 3 years after surgery for the young group, especially in the second year after surgery, the incidence of disease progression in the young group was 55.0%, higher than 26.5% in middle-old group ( P=0.025). The 3-year and 5-year disease-free survival (DFS) rates for the young group were 63.7% and 58.2%, lower than 81.0% and 74.3% in the middle-old group ( P=0.016), respectively. The 3-year and 5-year overall survival in the middle-old group (OS) rates for the young group were 85.4% and 69.2%, lower than 93.6% and 84.1% in the middle-old group ( P=0.033), respectively. The multivariate analysis showed that, response of primary tumor ( HR=4.804, 95% CI: 1.360-16.973) and total number of dissected lymph nodes ( HR=4.336, 95% CI: 1.739-10.809) in the young group were independent prognostic factors related to DFS. The total dissected number of lymph nodes( HR=3.295, 95% CI: 1.076-10.091)was an independent prognostic factor related to OS. In the middle-old group, response of primary tumor ( HR=2.626, 95% CI: 1.354-5.091), ypTNM stage (ypTNM Ⅲ: HR=5.837, 95% CI: 2.968-11.479) and tumor location distance from the anal verge ( HR=0.500, 95% CI: 0.308-0.812) were independent prognostic factors related to DFS. Lymphovascular invasion ( HR=0.500, 95% CI: 0.308-0.812) and ypTNM stage (ypTNM Ⅲ: HR=16.322, 95% CI: 5.049-52.771) were independent prognostic factors related to OS. Conclusions:Young onset rectal cancer patients are associated with shorter operation time interval, advanced pathological stage and poorer prognosis. More intensive adjuvant treatment and post-treatment surveillance should be conducted to young onset rectal cancer with NCRT.

Objective:To explore the risk factors for regional lymph node (RLN) metastasis in colorectal cancer patients with mismatch repair deficiency (dMMR).Methods:The data of 357 dMMR colorectal cancer patients who underwent surgery in National Cancer Center from January 2012 to December 2016 was retrospectively analyzed. Univariate and multivariate analysis were used to identify the risk factors for RLN metastasis.Results:Among the 357 patients, 204 were male and 153 were female, 61.6% (220/357) lesion located in right half colon, while the other 16.2% (58/357) located in rectum. Univariate analysis showed that tumor size, differentiation, lymphovascular invasion, tumor deposit, postoperative pathologic T stage (pT), the number of negative lymph nodes and the expression of the MSH6 protein were significantly associated with RLN metastasis ( P<0.05). All of the patients with well differentiation tumors (15 patients) or staged pT1 (13 patients) had no RLN metastasis. Multivariate analysis showed that tumor differentiation ( OR=2.582, 95% CI=1.567-4.274, P<0.001), pT ( OR=3.778, 95% CI=1.448-12.960, P=0.015) and the expression of MSH6 protein ( OR=2.188, 95% CI=1.159-4.401, P=0.021) were independent risk factors for RLN metastasis. Conclusions:The postoperative pT stage, tumor differentiation and the expression of MSH6 protein are independent risk factors for RLN metastasis of dMMR colorectal cancer. Preoperative assessment of these factors may further improve the accuracy of predicting the risk of RLN metastasis.

Objective:To explore the application value of the conditional disease-free survival (cDFS) analysis in predicting prognosis of stage-specific rectal cancer patients underwent neoadjuvant chemoradiotherapy (nCRT).Methods:Clinicopathologic data of 436 patients with rectal cancer received nCRT and radical operation in Cancer Hospital, Chinese Academy of Medical Sciences between January 2004 and December 2016 were retrospectively reviewed. With reference to conditional probability, the 3-year cDFS of patients at different ypTNM stage after completion of nCRT was estimated using the Kaplan-Meier method.Results:There were 66 patients of ypTNM stage 0 (pathological complete response), 87 patients of ypTNM stage Ⅰ, 135 patients of ypTNM stage Ⅱ and 148 patients of ypTNM stage Ⅲ. The 3-year accumulated DFS of patients with ypTNM stage 0, ypTNM stage Ⅰ, ypTNM stage Ⅱ, and ypTNM stage Ⅲ were 97.0%, 93.1%, 85.2%, and 64.2%, respectively. On the condition of postoperactive disease-free survival for 1 year, 2 years, 3 years, 4 years, and 5 years, the corresponding 3-year cDFS of patients at ypTNM stage 0 were 97.0%, 95.5%, 96.9%, 98.4%, 100.0%, respectively. The corresponding 3-year cDFS of patients at ypTNM Ⅲ were 68.2%, 79.3%, 86.3%, 92.1%, 96.4%, respectively. The more advanced ypTNM staging resulted in the more improvement of 3-year cDFS being acquired.Conclusion:cDFS is a better method to reflect the dynamic changes of the prognosis of rectal cancer patients with nCRT in different ypTNM stage, and it is useful to guide the clinicians to assess the prognosis and propose appropriate surveillance.

Objective To analyze the clinicopathological features and differential diagnosis of interdigitating dendritic cell sarcoma (IDCS). Methods The clinical pathological features of 7 IDCS were analyzed. Among them, the follow?up results of 6 cases were available. Results Among the 7 IDCS patients, 4 cases were male and 3 were female. The age of the patients ranged from 26 to 69 years.Three cases were originated from lymph nodes and 4 cases were originated from skin, stomach, adrenal gland and mesentery, respectively. Microscopically, the tumor cells presented as fascicular and storiform proliferation and infiltrated by lymphocytes. The tumor cells were short?spindle or ovoid, with indistinct border of cytoplasm. The immunohistochemistry results showed that tumor cells were S?100, Vim, CD68 and CD163 positive, and AE1／AE3, EMA, CD117, CD34, Desmin, SMA, CD1α, CD21, CD23, CD35, HMB45, Melan?A, MelanPan and ALK negative.The BRAF mutation and clonal rearrangement of T and B cells were not detected. Among the follow?up period of 7 IDCS patients, 3 occurred disease progressions. Conclusions IDCS is extremely rare with unique pathological features, and its lesion is not limited to the lymph node. The IDCS patients with extensive lesions may have worse prognose. The differential diagnosis of IDCS includes other histiocytic and dendritic cell neoplasms, malignant melanoma and soft tissue neoplasms.

Objective To evaluate the safety and efficacy of surgical treatment after neoadjuvant chemotherapy (NCT) for patients with cT4N+colon cancer, and to explore whether the indication of NCT for colon cancer can be extended from cT4b to cT4N+. Methods The clinical data of 40 patients with cT4N+colon cancer who underwent neoadjuvant chemotherapy followed by surgical treatment was retrospectively analyzed. The safety of neoadjuvant chemotherapy, surgical complications, R0 resection rate, tumor regression grade and prognosis were evaluated. Results Of the 40 patients, 23 were male and 17 were female; the median age was 57 years old. All patients were well tolerated with chemotherapy, and only one case (1／40, 2.5%) had grade 3 chemotherapy?related adverse event. They all underwent surgery after chemotherapy, and 95.0%(38／40) achieved microscopically clear resection (R0). Of the 11 patients with cT4b, 54.5%( 6／11) had undergone multivisceral resection ( MVR). Postoperative pathological results showed that 12 patients had moderate to severe tumor regression, including one ( 1／40, 2.5%) achieved pathologic complete response (pCR).29(72.5%) and 22 (55.0%) patients achieved down?staging of tumor T stage and N stage, respectively. The occurrence of surgical complications was 22.5%(9／40), including one case of anastomotic leakage (1／40, 2.5%). The 3?year disease?free survival and overall survival of the whole group were 75.0% and 80.0%, respectively. Conclusion Surgery after neoadjuvant chemotherapy is safe and effective for patients with cT4N+colon cancer, therefore indications for neoadjuvant chemotherapy for advanced colon cancer can be extended to cT4N+ stage.

Objective:To explore the clinicopathological and prognostic features of young onset patients with middle-low rectal cancer who received neoadjuvant chemoradiotherapy (NCRT).Methods:After NCRT, a total of 441 patients with primary middle-low rectal cancer treated with radical surgery at the Cancer Hospital, Chinese Academy of Medical Sciences (CHCAMS) from January 2004 to December 2016 were included. According to the age of disease onset, the patients were divided into the young group (51cases) and the middle-old group (390 cases), and the clinicopathological characteristics and survival of these patients were analyzed.Results:In the young group, 68.6% of patients received radical surgery within 7 weeks after NCRT, which was higher than 52.8% in the middle-old group ( P=0.047). The stage ypTNM Ⅲ in the young group was 51.0%, higher than 34.1% in the middle-old group ( P=0.027). The stage ypN+ in the young group was 51.0%, higher than 34.1% in the middle-old group ( P=0.047), The incidence of disease progression in the young group was 39.2%, higher than 25.1% in the middle-old group ( P=0.049). The incidence of distant metastasis in the young group was 35.3%, higher than 21.5% in the middle-old group( P=0.044). Most cases of disease progression occurred in the first 3 years after surgery for the young group, especially in the second year after surgery, the incidence of disease progression in the young group was 55.0%, higher than 26.5% in middle-old group ( P=0.025). The 3-year and 5-year disease-free survival (DFS) rates for the young group were 63.7% and 58.2%, lower than 81.0% and 74.3% in the middle-old group ( P=0.016), respectively. The 3-year and 5-year overall survival in the middle-old group (OS) rates for the young group were 85.4% and 69.2%, lower than 93.6% and 84.1% in the middle-old group ( P=0.033), respectively. The multivariate analysis showed that, response of primary tumor ( HR=4.804, 95% CI: 1.360-16.973) and total number of dissected lymph nodes ( HR=4.336, 95% CI: 1.739-10.809) in the young group were independent prognostic factors related to DFS. The total dissected number of lymph nodes( HR=3.295, 95% CI: 1.076-10.091)was an independent prognostic factor related to OS. In the middle-old group, response of primary tumor ( HR=2.626, 95% CI: 1.354-5.091), ypTNM stage (ypTNM Ⅲ: HR=5.837, 95% CI: 2.968-11.479) and tumor location distance from the anal verge ( HR=0.500, 95% CI: 0.308-0.812) were independent prognostic factors related to DFS. Lymphovascular invasion ( HR=0.500, 95% CI: 0.308-0.812) and ypTNM stage (ypTNM Ⅲ: HR=16.322, 95% CI: 5.049-52.771) were independent prognostic factors related to OS. Conclusions:Young onset rectal cancer patients are associated with shorter operation time interval, advanced pathological stage and poorer prognosis. More intensive adjuvant treatment and post-treatment surveillance should be conducted to young onset rectal cancer with NCRT.

Objective:To explore the risk factors for regional lymph node (RLN) metastasis in colorectal cancer patients with mismatch repair deficiency (dMMR).Methods:The data of 357 dMMR colorectal cancer patients who underwent surgery in National Cancer Center from January 2012 to December 2016 was retrospectively analyzed. Univariate and multivariate analysis were used to identify the risk factors for RLN metastasis.Results:Among the 357 patients, 204 were male and 153 were female, 61.6% (220/357) lesion located in right half colon, while the other 16.2% (58/357) located in rectum. Univariate analysis showed that tumor size, differentiation, lymphovascular invasion, tumor deposit, postoperative pathologic T stage (pT), the number of negative lymph nodes and the expression of the MSH6 protein were significantly associated with RLN metastasis ( P<0.05). All of the patients with well differentiation tumors (15 patients) or staged pT1 (13 patients) had no RLN metastasis. Multivariate analysis showed that tumor differentiation ( OR=2.582, 95% CI=1.567-4.274, P<0.001), pT ( OR=3.778, 95% CI=1.448-12.960, P=0.015) and the expression of MSH6 protein ( OR=2.188, 95% CI=1.159-4.401, P=0.021) were independent risk factors for RLN metastasis. Conclusions:The postoperative pT stage, tumor differentiation and the expression of MSH6 protein are independent risk factors for RLN metastasis of dMMR colorectal cancer. Preoperative assessment of these factors may further improve the accuracy of predicting the risk of RLN metastasis.