Well-Differentiated Neuroendocrine Tumors of the Appendix in Children and Adolescents: A Clinicopathologic Study.

BACKGROUND AND AIMS: Pediatric neuroendocrine tumors (NET) of the GI tract are rare and appendiceal NET are typically incidental. Few studies have been done in the pediatric population and practice guidelines are mainly based on adult data. There are currently no diagnostic studies specific for NET. Our study aimed to identify clinical, radiological, and pathological findings in pediatric appendiceal NET, test criteria for follow up surgical treatment, review potential prognostic pathological findings, and possible pre-operative diagnostic radiological studies. MATERIALS AND METHODS: A retrospective data search was conducted for well-differentiated NET of the appendix in patients ≤21 years between 1/1/2003 and 7/1/2022. Available clinical, radiologic, pathological, and follow-up information was recorded. RESULTS: Thirty-seven patients with appendiceal NET were identified. No masses were reported in the patients who underwent presurgical imaging. Appendectomy samples showed NET (0.2->4 cm), most located in the tip. Most cases were WHO G1 (34/37), with negative margins (n = 25). Sixteen cases extended to the subserosa/mesoappendix (pT3). Lymphovascular (6), perineural (2), and both lymphovascular and perineural invasion were also noted (2). The specified tumor stages were pT1 (10/37), pT3 (16/37), and pT4 (4/37). Patients who underwent laboratory testing for chromogranin A (20) and urine 5HIAA (11) had normal limits. Subsequent surgical resection was recommended in 13 cases and performed in 11. To date, all patients have no recurrent or additional metastatic disease. CONCLUSIONS: Our study showed that all pediatric well-differentiated appendiceal NET were incidentally found as part of acute appendicitis management. Most NET were localized with low-grade histology. Our small cohort support the previously suggested management guidelines with follow up resection in certain cases. Our radiologic review didn't identify a best modality for NET. Comparing cases with and without metastatic disease, no tumors under 1 cm had metastasis, but serosal and perineural invasion along with G2 status were associated with metastasis in our limited study.

Secretory Carcinoma in Children and Young Adults: A Case Series.

Secretory carcinoma (SC), previously known as mammary analogue secretory carcinoma, is a rare salivary gland neoplasm that typically presents as a slow-growing painless lesion in the head and neck. SC occurs mainly in adults but has been described in children with the youngest reported patient diagnosed at five years of age. In children the gender distribution has been reported as female to male ratio of 1:1.2. SC is generally considered a low-grade malignancy with characteristic morphological features and immunological profile. SC also harbors ETV6-NTRK3 fusion (t(12;15)(p13:q25)). Surgical resection with or without lymph node dissection is the standard treatment, with generally favorable clinical outcomes. Here we present a single institution case series of six patients (ages 9-21) with SC and a review of the previously described pediatric cases. Our small series showed male predominance in pediatric patients with predominantly low-grade and stage tumors. All cases underwent complete surgical resections and when follow up is available there was no evidence of recurrences or metastases. To the best of our knowledge, this is the only SC case series comprised exclusively of pediatric and youth patients.

Plasmacytoid urothelial carcinoma: a rapid autopsy case report with unique clinicopathologic and genomic profile.

BACKGROUND: Rapid ("warm") autopsies of patients with advanced metastatic cancer provide important insight into the natural history, pathobiology and histomorphology of disease in treatment-resistant tumors. Plasmacytoid urothelial carcinoma (PUC) is a rare variant of urothelial carcinoma characterized by neoplastic cells morphologically resembling plasma cells. PUC is typically aggressive, high-stage at presentation, and associated with poor outcomes. Recurrence is common in PUC, with the majority of recurrences occurring in the peritoneum. CASE PRESENTATION: Here, we report rapid autopsy findings from a patient with recurrent PUC. The patient had persistent pain after cystoprostatectomy, although initial post-operative imaging showed no evidence of disease. Imaging obtained shortly before his death showed only subtle growth along vascular tissue planes; however, extensive disease was seen on autopsy. Plasmacytoid tumor cells formed sheets involving many serosal surfaces. Molecular interrogation confirmed a mutation in CDH1 exon 12 leading to early truncation of the CDH1 protein in the tumor cells. CONCLUSIONS: The sheet-like growth pattern of PUC makes early phases of disease spread much more difficult to capture on cross-sectional imaging. Alternative forms of surveillance may be required for detection of recurrent PUC, and providers may need to treat based on symptoms and clinical suspicion.

Clinical utility and concordance of upper urinary tract cytology and biopsy in predicting clinicopathological features of upper urinary tract urothelial carcinoma.

Five percent of urothelial carcinoma occurs in the upper urinary tract (UUT), a challenging location to biopsy. We aim to evaluate concordance between biopsy, cytology, and resection specimens in a large upper tract urothelial carcinoma (UTUC) cohort. One hundred seventeen UTUC resections with UUT biopsy and/or cytology specimens from 2000 to 2016 were retrieved; pathologic material was re-reviewed, evaluated for concordance, and correlated with clinical information. Fourteen percent of preoperative biopsies, including 8 from the renal pelvis and 6 from the ureter, lacked neoplastic diagnoses. Seventy-seven percent of diagnostic biopsies included subepithelial tissue; 11% demonstrated reclassification of grade and 30% demonstrated reclassification of invasion status. Twenty-six percent of renal pelvis UTUC and 36% of ureter UTUC were invasive only on resection. Of 18 UTUCs reclassified from noninvasive high-grade papillary urothelial carcinoma to invasive high-grade papillary urothelial carcinoma, 39% had prior radical cystectomy (versus 8% invasive UTUC and 11% noninvasive UTUC with concordant biopsies). Most high-grade UTUC (88%) and some low-grade UTUC (58%) resections had abnormal cytology results. Biopsy-resection pairs with concordant invasion status and pairs with discordant invasion status showed similar rates of recurrence (38% versus 38%) and metastasis (25% versus 27%). Fourteen percent of UUT biopsies lacked diagnostic neoplastic material. Grade concordance between biopsy and resection was high (89%), but 30% of cases showed invasion only on resection. Subepithelial tissue was less commonly present in ureter biopsies, particularly from the midureter or proximal ureter. UTUC in patients with prior cystectomy were more likely to show invasion on resection but not biopsy.

Unexpected disseminated histoplasmosis detected by bone marrow biopsy in a solid organ transplant patient.

Disseminated histoplasmosis and hemophagocytic lymphohistiocytosis show overlapping features, which require careful contextual interpretation. Histopathologic evaluation can potentially rapidly identify cases of possible histoplasmosis. A high index of clinical suspicion, particularly in endemic areas and in a setting of immunosuppression, is critical to appropriate diagnosis and treatment.