Nick Shillingford

Exome sequencing identifies BRAF mutations in papillary craniopharyngiomas

Craniopharyngiomas are epithelial tumors that typically arise in the suprasellar region of the brain. Patients experience substantial clinical sequelae from both extension of the tumors and therapeutic interventions that damage the optic chiasm, the pituitary stalk and the hypothalamic area. Using whole-exome sequencing, we identified mutations in CTNNB1 (β-catenin) in nearly all adamantinomatous craniopharyngiomas examined (11/12, 92%) and recurrent mutations in BRAF (resulting in p.Val600Glu) in all papillary craniopharyngiomas (3/3, 100%). Targeted genotyping revealed BRAF p.Val600Glu in 95% of papillary craniopharyngiomas (36 of 39 tumors) and mutation of CTNNB1 in 96% of adamantinomatous craniopharyngiomas (51 of 53 tumors). The CTNNB1 and BRAF mutations were clonal in each tumor subtype, and we detected no other recurrent mutations or genomic aberrations in either subtype. Adamantinomatous and papillary craniopharyngiomas harbor mutations that are mutually exclusive and clonal. These findings have important implications for the diagnosis and treatment of these neoplasms.

MicroRNA profiling in mucosal biopsies of eosinophilic esophagitis patients pre and post treatment with steroids and relationship with mRNA targets.

Background The characterization of miRNAs and their target mRNAs involved in regulation of the immune process is an area of intense research and relatively little is known governing these processes in allergic inflammation. Here we present novel findings defining the miRNA and mRNA transcriptome in eosinophilic esophagitis (EoE), an increasing recognized allergic disorder. Methods Esophageal epithelial miRNA and mRNA from five paired biopsies pre- and post-treatment with glucocorticosteroids were profiled using Taqman and Affymetrix arrays. Validation was performed on additional paired biopsies, untreated EoE specimens and normal controls. Differentially regulated miRNAs and mRNAs were generated, within which miRNA-mRNA target pairs with high predicted confidence were identified. Results Compared to the post-glucocorticoid treated esophageal mucosa, of all the 377 miRNA sequences examined, 32 miRNAs were significantly upregulated and four downregulated in the pre-treated biopsies. MiR-214 was the most upregulated (150 fold) and miR-146b-5b, 146a, 145, 142-3p and 21 were upregulated by at least 10 fold. Out of 12 miRNAs chosen for validation by qRT-PCR, five (miR-214, 146b-5p, 146a, 142-3p and 21) were confirmed and 11 shared the same trend. When the expression of the 12 miRNAs in the EoE mucosa was compared to unrelated normal mucosa, six (miR-214, 146b-5p, 146a, 21, 203, and 489) showed similar significant changes as in the paired samples and 10 of them shared the same trend. In the same five pairs of samples used to profile miRNA, 311 mRNAs were down-regulated and 35 were up-regulated in pre-treated EoE mucosa. Among them, 164 mRNAs were identified as potential targets of differentially regulated miRNAs. Further analysis revealed that immune-related genes, targeted and non-targeted by miRNAs, were among the most important genes involved in the pathogenesis of EoE. Conclusions Our findings add to the accumulating body of data defining a regulatory role for miRNA in immune and allergic processes.

Villin immunohistochemistry is a reliable method for diagnosing microvillus inclusion disease.

Microvillus inclusion disease (MVID) is a rare congenital disorder that manifests early in infancy as intractable watery diarrhea. The entity is characterized morphologically by a deficient brush border and apical cytoplasmic inclusions within absorptive cells (enterocytes) due to misplaced assembly of brush border proteins. The diagnosis is based upon histopathology, special stains, immunohistochemistry (IHC), and ultimately upon electron microscopy. Currently, the periodic acid-Schiff stain (PAS) and CD10 IHC are commonly used as adjuncts, but in addition to brush border structures, they stain a variety of apical cytoplasmic inclusions and organelles, thereby interfering with recognition of microvillus inclusions. Villin is a protein that specifically binds to the actin core bundle of microvilli. We utilized villin IHC in formalin-fixed paraffin-embedded gastrointestinal biopsies from 6 patients with MVID, 5 with celiac disease, and 17 children with normal intestinal biopsies and compared the results with those obtained with CD10 IHC and PAS staining. All MVID cases had confirmatory electron microscopy at the time of diagnosis. Villin immunoreactivity was restricted to the brush border in the control groups. In MVID, villin IHC showed attenuation or loss of the surface brush border and also highlighted the cytoplasmic microvillus inclusions with clarity. In MVID, CD10 IHC and the PAS stain also showed attenuation or loss of the surface brush border, but staining of a variety of cytoplasmic structures largely obscured the microvillus inclusions. In sum, villin IHC is a reliable and superior adjunct in the diagnosis of MVID. Study of additional cases will determine whether villin IHC would obviate the need for electron microscopic confirmation.

Hepatic Inflammation May Influence Liver Stiffness Measurements By Transient Elastography in Children and Young Adults.

Objectives: Transient elastography (TE) measures liver stiffness to assess fibrosis. Studies in adults have shown that inflammation increases stiffness, leading to an overestimation of fibrosis. We investigated the contribution of inflammation to liver stiffness measurements (LSMs) in children/young adults. Methods: This was a cohort analysis of children/young adults who underwent TE within 1 year of liver biopsy. Alanine aminotransferase (ALT) was obtained within 30 days of the biopsy and LSM. Fibrosis was assessed by METAVIR stage and inflammation by ALT and Ishak score. Data were stratified into METAVIR F0–F2 versus F3–F4. Change between ALT and LSM over time was also assessed. Results: A total of 154 patients (50% male patients) ages 3 weeks to 24 years (18% <3 years) were studied. Diagnoses included autoimmune (N = 38, 25%), viral (N = 25, 16%), cholestasis (N = 17, 11%), fatty liver (N = 9, 6%), biliary atresia (N = 8, 5%), metabolic (N = 5, 3%), allograft rejection (N = 4, 3%), and other (N = 48, 31%). Thirty-four percent of patients had F3–F4. In patients with F0–F2, the proportion of those with LSM >8.6 kPa increased with increasing ALT (P = 0.002). In patients with F3–F4, there was no association between ALT and LSM (P = 0.17). A correlation between change in ALT and LSM was observed in patients with no/minimal fibrosis and inflammatory liver diseases (r = 0.33). Conclusions: In children with no/minimal hepatic fibrosis and inflammatory liver disease, high ALT values are associated with LSM in the range typical of advanced fibrosis. However, with more advanced fibrosis, inflammation does not appear to contribute to LSM. Caution must be taken when interpreting LSM for assessing fibrosis severity in the setting of inflammation.

The diagnostic and prognostic value of SALL4 in hepatoblastoma.

To investigate the expression of spalt‐like transcription factor 4 (SALL4), a regulator of embryonal development, in three epithelial components of hepatoblastoma (HB) and the relationship between SALL4 expression levels and patients’ clinicopathological features.

Citrulline levels following proximal versus distal small bowel resection

PURPOSE Citrulline, a nonprotein amino acid synthesized by enterocytes, is a biomarker of bowel length and the capacity to wean from parenteral nutrition. However, the potentially variant effect of jejunal versus ileal excision on plasma citrulline concentration [CIT] has not been studied. This investigation compared serial serum [CIT] and mucosal adaptive potential after proximal versus distal small bowel resection. METHODS Enterally fed Sprague-Dawley rats underwent sham operation or 50% small bowel resection, either proximal (PR) or distal (DR). [CIT] was measured at operation and weekly for 8 weeks. At necropsy, histologic features reflecting bowel adaptation were evaluated. RESULTS By weeks 6-7, [CIT] in both resection groups significantly decreased from baseline (P<0.05) and was significantly lower than the concentration in sham animals (P<0.05). There was no difference in [CIT] between PR and DR at any point. Villus height and crypt density were higher in the PR than in the DR group (P≤0.02). CONCLUSION [CIT] effectively differentiates animals undergoing major bowel resection from those with preserved intestinal length. The region of intestinal resection was not a determinant of [CIT]. The remaining bowel in the PR group demonstrated greater adaptive potential histologically. [CIT] is a robust biomarker for intestinal length, irrespective of location of small intestine lost.

Histopathologic Finding of Both Gastric and Respiratory Epithelia in a Lingual Foregut Cyst.

Foregut cysts are uncommon, mucosa-lined congenital lesions that may occur anywhere along the gastrointestinal or respiratory tract and typically present within the first year of life. Although infrequent, these cysts may generate feeding or respiratory difficulties depending on the size and location of the lesion. Foregut cysts of the oral cavity are rarely seen and of those cases localized to the tongue are even more uncommon. We describe a 4-month-old girl with a foregut cyst involving the floor of mouth and anterior tongue. Subsequent histologic analysis demonstrated a cyst lined with both gastric and respiratory epithelia. This case represents an extremely rare finding of both gastric and respiratory epithelia lined within a single cystic structure in the tongue. Although a very rare finding, a foregut cyst should be on the differential diagnosis of any lesion involving the floor of mouth or tongue in an infant or child.

Mullerian-Type Ciliated Cyst of the Thigh with PAX-8 and WT1 Positivity: A Case Report and Review of the Literature

Mullerian-type ciliated cysts are uncommon lesions usually found in the lower extremities and perineal region of young females. They have however been reported in males and in other anatomic sites. The cyst lining is typically positive for estrogen receptor (ER), progesterone receptor (PR), PAX-8, and WT1 immunohistochemical stains. This staining pattern has led to the notion that these cysts are of Müllerian origin. The vast majority of cases are located in the dermis where the preferred nomenclature is cutaneous ciliated cyst (CCC). We report a case of Müllerian-type ciliated cyst in the thigh of a 16-year-old girl. Unlike most of the cases reported in the English literature, this cyst was not centered in the dermis. Only a few other cases of Müllerian-type ciliated cysts with no cutaneous connection have been reported. We propose the term ectopic Müllerian cyst for this rare subset of lesions that are not skin based as is the current case.

Bronchial Mucoepidermoid Carcinoma With the Classic MAML2 Gene Rearrangement in a 2-year-old Boy.

Pulmonary mucoepidermoid carcinoma (PMEC) is rare. To date, primary PMEC has not been reported in a child younger than 3 years of age. We report a case of a 2-year-old boy who presented with 3 episodes of wheezing, cough, and fever over a period of 1 month. Radiologic findings were consistent with foreign body aspiration with consequent bronchial obstruction. Bronchoscopy was performed and attempts to retrieve the foreign body resulted in a biopsy of a fleshy lesion. By histology, the lesion was an epithelial neoplasm comprising cells arranged in a nested pattern. The neoplastic cells were round with round nuclei and amphophilic, vacuolated cytoplasm. Our diagnosis was low-grade salivary gland-type carcinoma of the bronchus. The pneumonectomy specimen showed a well-circumscribed, polypoid intrabronchial mass measuring 2.1 cm in greatest dimension. Histologic examination of the tumor showed an admixture of intermediate cells which were predominant, a small number of mucus cells and rare foci of squamous cells. The final diagnosis rendered was a low-grade mucoepidermoid carcinoma of the bronchus. Accurate diagnosis of PMEC can be challenging on limited biopsy material as seen in the case reported here. The use of molecular studies such as MAML2 gene rearrangement may facilitate diagnosis in difficult cases. Increased awareness of this entity and further molecular studies are needed for a better understanding of the pathogenesis of PMEC. To date, the reported age range for primary bronchial mucoepidermoid carcinoma is between 3 years and 78 years. This case represents the youngest patient reported in the English literature.

An ectopic renin-secreting adrenal corticoadenoma in a child with malignant hypertension

A previously healthy 7‐year‐old male presented with hypertensive emergency, hypokalemia, and elevated plasma renin activity and aldosterone levels. There was no evidence of virilization or cushingoid features. MRI of the abdomen revealed a large (5 × 5 × 3 cm) peripherally enhancing, heterogeneous mass arising from the left adrenal gland. The patient was treated for a suspected pheochromocytoma. However, his blood pressure was not responsive to alpha‐blockade. Blood pressure was controlled with a calcium channel blocker and an angiotensin‐converting enzyme (ACE) inhibitor. A complete surgical resection of the mass was performed. Postoperatively, his blood pressure normalized and he did not require antihypertensives. On pathological examination, the tumor tissue stained negative for chromogranin and positive for renin. The final diagnosis was renin‐secreting adrenal corticoadenoma, an extremely rare adrenal tumor not previously reported in a pediatric patient. Malignant hypertension due to a renin‐secreting tumor may need to be distinguished from a pheochromocytoma if alpha‐adrenergic blockade is ineffective.