INTRODUCTIONGranulomatous cervicofacial lymphadenitis (GCL) is not uncommon in children. Nontuberculous mycobacteria (NTM) seem to be the predominant cause. We sought to study the clinical and microbiological profile of patients with GCL, and identify features that may impact outcome.

METHODSChildren aged < 16 years who presented to KK Women's and Children's Hospital, Singapore, between January 1998 and December 2006, and who had GCL were identified from laboratory records. Clinical and laboratory data was collected and analysed for risk factors for patients with positive lymph node cultures, and for patients with and without recurrence after treatment.

RESULTSIn all, 60 children were identified, with a median age of 56 (interquartile range [IQR] 34-101) months. Median duration of symptoms before presentation was 5 (IQR 4-8) weeks. The majority presented with single (73.3%) or unilateral (96.7%) lymphadenopathy, located in the submandibular, preauricular/parotid or infra-/post-auricular region (76.7%). Out of 51 patients, 26 (51.0%) had a tuberculin skin test reading of ≥ 10 mm. Out of 52 patients, 10 (19.2%) had positive mycobacterial cultures, which included seven isolates of NTM. Out of 34 cases, tuberculous polymerase chain reaction was positive in 11 (32.4%). With regard to recurrence after initial treatment, age < 5 years at presentation was found to be a predictor for recurrence (p = 0.008), while initial complete excision of affected nodes predicted no recurrence (p = 0.003).

CONCLUSIONIn our study, younger age was noted to be associated with a higher chance of recurrence, while complete excision of the involved node at initial presentation predicted non-recurrence.

Adolescent ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Lymphadenitis ; diagnosis ; epidemiology ; microbiology ; Lymphatic Diseases ; diagnosis ; microbiology ; Male ; Mycobacterium ; Mycobacterium Infections ; diagnosis ; epidemiology ; microbiology ; Recurrence ; Retrospective Studies ; Singapore ; Treatment Outcome ; Tuberculin Test

Objective:To study clinical pathological characteristics, immunohistochemical, molecular genetical changes and prognosis in pediatric eosinophilic solid and cystic renal cell carcinoma (ESC RCC) with TSC2 gene mutations.Methods:The tissue samples were collected from two pediatric ESC RCC patients between 2017 and 2018. The tissues were subjected to histological examination and immunohistochemistry using EnVision system. The TFE3, TFEB gene rearrangements were tested using FISH and molecular genetic study. The paraffin sections were used for DNA extraction, PCR amplification and NGS sequencing.Results:The two patients with ESC RCC were both male, aged at 9 years and 8 months, and 13 years, respectively. The tumors were from the right kidney, 5 cm and 7 cm in size, respectively, with solid and cystic changes in cross section, and grey-reddish or grey-whitish fish meat appearance. Microscopic observation revealed the tumors had fibrous capsules, which were infiltrated by the tumor cells. The tumor cells were diffusely distributed, round-shaped, or polygon-shaped, and had voluminous cytoplasm, eosinophilic cytoplasm, various sizes of vacuoles and clear cell-like appearance. There were papillary structures in some areas, with visible fiber septa. The nuclei were round and vesicular, with multi-nucleated cells and megakaryocytes. The mitoses were not seen. A few cystic structures were visible in different sizes, and capsule walls were covered with a single layer of spike-like tumor cells. Thick-walled blood vessels were seen in the stroma, with focal lymphocytic infiltration, eosinophilic necrosis, calcifications and cholesterol crystals. Immunohistochemistry of the tumor cells was positive for PAX8 (diffuse), CK20 (focal), CKpan (focal), CK10 (1 focal, 1 diffuse), INI1, vimentin, CD68, and Ki-67 (5%~10%); the tumor cells were negative for HMB45, S-100, Melan A, p53, desmin, TFE3, CK7, CK19, EMA, CD56, CgA, Syn, CD30, CD117, WT1 and SMA. Molecular genetic study showed that TFE3 and TFEB gene rearrangements were not detected by FISH. NGS sequencing showed TSC2 p.Lys574Ter (0.198) was found in patient one and TSC2 p.Arg406Ter (0.355) in patient two.Conclusions:ESC RCC in children is a rare disease, and can be misdiagnosed easily. It has unique pathological characteristics, and immunohistochemical, molecular and genetic changes. The prognosis is relatively good.

Objective:To investigate the clinical and pathological features of pediatric NTRK-rearranged tumors.Methods:Four NTRK-rearranged soft tissue tumors and one renal tumor at Shanghai Children′s Medical Center, Shanghai Jiaotong University and Singapore KK Women′s and Children′s Hospital from January 2017 to September 2019 were identified. Pan-TRK immunohistochemistry, and the ALK and ETV6 gene break-apart fluorescence in situ hybridizations (FISH) were performed. NTRK gene rearrangement was detected using sequencing-based methods.Results:There were 3 males and 2 females in this study. The patients were between 3 months and 13 years of age. Histologically, the tumors were infiltrative spindle cell tumors with variable accompanying inflammatory cells. Immunohistochemistry showed positive reactivity for pan-TRK in all tumors, with nuclear staining for NTRK3 fusion, and cytoplasmic staining for NTRK1 fusion. The molecular testing revealed NTRK gene fusions (one each of TPM3-NTRK1, ETV6-NTRK3 and DCTN1-NTRK1, and two cases of LMNA-NTRK1). Two patients were receiving larotrectinib. The others were are well without disease, with follow-up durations of 9 to 29 months.Conclusions:NTRK-rearranged mesenchymal tumors from soft tissue sites and kidney are identified. A novel DCTN1-NTRK1 fusion is described. Pan-TRK immunohistochemistry is useful for diagnosis. NTRK-targeted therapy may be an option for unresectable, recurrent or metastatic cases.

Objective: To investigate the immunohistochemical staining of anaplastic lymphoma kinase (ALK; clone 1A4) in pediatric medulloblastoma (MB). Methods: Molecular subtyping was performed based on the NanoString and sequencing techniques for 44 pediatric MB cases at Children′s Hospital, Zhejiang University School of Medicine from 2014 to 2017. ALK expression was detected with EnVision immunhistochemistry using ALK clone 1A4 on whole section. Statistical analyses were performed to evaluate the correlation of protein expression with molecular subgroups. Results: The age ranged from 0.5 to 13.0 years with an average age of 5.8 years. There were 28 males and 16 females, and 31 classic, 5 desmoplastic nodular, 3 extensive nodular and 5 large cell/anaplastic MBs. Except three cases was unable classified, 41 MBs were classified into the four molecular groups: 5 in WNT group, 12 in SHH group, 9 in Group 3 and 15 in Group 4. Thirteen of 44 MB cases were positive staining for ALK, and the positive rate was 29.5%. Six cases were strong reaction, and 7 cases were weak. The expression of ALK at the protein level was associated with the WNT group (P<0.01). The characteristic perinuclear dot-like staining was only showed in WNT group. Conclusions The ALK immunhistochemistry using antibody clone 1A4 is a useful marker for the molecular subgroup detection of MB. The strong staining and perinuclear dot-like staining indicate as WNT group.