Cells of the human intestinal tract mapped across space and time.

The cellular landscape of the human intestinal tract is dynamic throughout life, developing in utero and changing in response to functional requirements and environmental exposures. Here, to comprehensively map cell lineages, we use single-cell RNA sequencing and antigen receptor analysis of almost half a million cells from up to 5 anatomical regions in the developing and up to 11 distinct anatomical regions in the healthy paediatric and adult human gut. This reveals the existence of transcriptionally distinct BEST4 epithelial cells throughout the human intestinal tract. Furthermore, we implicate IgG sensing as a function of intestinal tuft cells. We describe neural cell populations in the developing enteric nervous system, and predict cell-type-specific expression of genes associated with Hirschsprung's disease. Finally, using a systems approach, we identify key cell players that drive the formation of secondary lymphoid tissue in early human development. We show that these programs are adopted in inflammatory bowel disease to recruit and retain immune cells at the site of inflammation. This catalogue of intestinal cells will provide new insights into cellular programs in development, homeostasis and disease.

Gonadotrophin-independent Precocious Puberty Secondary to an Estrogen Secreting Adrenal Tumor.

BACKGROUND: Adrenal masses are rare in children and most commonly present with clinical features of virilization in the absence of activation of the pituitary axis-gonadotrophin-independent precocious puberty. OBSERVATIONS: We report an unusual case of a 7-year-old girl who presented with clinical signs suggestive of exposure to both androgens and estrogens. Imaging revealed a left-sided adrenal mass with no evidence of metastasis. She underwent successful laparoscopic unilateral adrenalectomy. Histology confirmed an adrenal adenoma. CONCLUSION: We conclude that adrenocortical tumors should be considered in children presenting with gonadotrophin-independent precocious puberty and raised estrogens.

Hodgkin Lymphoma Presenting With Spinal Cord Compression: Challenges for Diagnosis and Initial Management.

Hodgkin lymphoma (HL) can present with extra-nodal disease, but spinal cord compression is exceptionally rare. We describe a 15-year-old presenting with hip/back pain with normal initial examination. Persistent pain and raised inflammatory markers prompted further investigation with MRI, which revealed an epidural mass causing spinal cord compression. On examination, there was no palpable lymphadenopathy or cauda equina syndrome, but absent lower limb reflexes were noted. Following multidisciplinary discussion, it was determined that cauda equina syndrome was imminent and therefore surgical debulking was undertaken, both to prevent this complication and establish a diagnosis. At surgery, the tumor was highly vascular. Frozen section confirmed lesional material. Following surgery, and given the frozen section findings, a short course of steroids was commenced to reduce any peri-surgical edema. Unfortunately, histopathology was ultimately non-diagnostic, due to failure of immunohistochemistry on technically challenging material. Consequently, ultrasound-guided excision biopsy of a (non-palpable) cervical lymph node was performed five days later; histopathology showed typical effacement of the normal architecture and a conspicuous population of CD15/CD30-positive larger pale cells present, confirming nodular sclerosis classic HL, despite recent steroids. We review the available literature for HL presenting with spinal cord compression and describe the challenges for diagnosis and initial management in such cases.

Recurrent ovarian immature teratoma in a 12-year-old girl: Implications for management.

Immature teratomas (IT) are rare and recurrences uncommon. A 12-year-old female with grade 3 (high-grade) ovarian IT underwent surgical resection but experienced early recurrences; the first was treated with surgery but the second was metastatic and managed with chemotherapy, resulting in growing-teratoma-syndrome and need for further surgery. She now remains well in uneventful clinical follow-up. We believe chemotherapy could be reserved for very carefully selected recurrent IT cases, which may alter the natural history of disease.

Lingual Alveolar Soft Part Sarcoma in a 1-Year-Old Infant: Youngest Reported Case With Characteristic ASPSCR1-TFE3 Fusion.

Alveolar soft part sarcoma (ASPS) is an exceptionally rare non-rhabdomyosarcomatous soft tissue sarcoma (NRSTS), characterized by the translocation t(X;17) p(11.2;q25). This translocation results in the chimeric ASPSCR1-TFE3 transcription factor which drives tumorigenesis. Complete surgical resection is crucial in allowing a successful outcome in these cases. Here, we describe an 11-month-old female infant who presented with a well-circumscribed lesion of the tongue, with the clinical and radiologic appearances of an infantile hemangioma. This led to an initial plan for surveillance management. However, the mass continued to enlarge and the lesion was therefore biopsied when the infant was 17 months old. Histology showed plump epithelioid tumor cells, in many places lining pseudoalveolar spaces. Occasional Pas-D inclusions were present in the cytoplasm. Immunostaining showed nuclear positivity for TFE-3. Real-time quantitative polymerase chain reaction testing confirmed the presence of ASPSCR1-TFE3 fusion transcripts, characteristic of the translocation t(X;17) p(11.2;q25) observed in ASPS. This represents the youngest reported ASPS case with a confirmed molecular diagnosis. Complete surgical resection was undertaken and a surveillance imaging schedule implemented. This case highlights the need for regular review of the initial diagnosis and the importance of multidisciplinary discussion and early biopsy where the clinical course does not follow that expected for the putative (nonhistologically confirmed) diagnosis.

Determining the contribution of NPM1 heterozygosity to NPM-ALK-induced lymphomagenesis.

Heterozygous expression of Nucleophosmin (NPM1) predisposes to hematological malignancies in the mouse and cooperates with Myc in lymphomagenesis. NPM1 is therefore regarded as a haploinsufficient tumor suppressor. Heterozygous loss of NPM1 occurs as a result of the t(2;5), which generates the oncogenic fusion tyrosine kinase, NPM-anaplastic lymphoma kinase (ALK), a molecule underlying the pathogenesis of anaplastic large cell lymphoma (ALCL). Given the aforementioned role of NPM1 as a tumor suppressor, we hypothesized that NPM1 heterozygosity would cooperate with NPM-ALK in lymphomagenesis. In the event, we observed no difference in tumor latency, incidence or phenotype in NPM-ALK-transgenic mice heterozygous for NPM1 relative to transgenic mice expressing both NPM1 alleles. We propose that although the t(2;5) simultaneously reduces NPM1 allelic dosage and creates the NPM-ALK fusion protein, the two events do not cooperate in the pathogenesis of ALCL in our mouse model. These data indicate that a tumor-suppressive role for NPM1 may depend on cellular and/or genetic context.

Spontaneous regression of an EBV-associated monoclonal large B cell proliferation in the mastoid of a young child following surgical biopsy.

We report the spontaneous regression of an Epstein-Barr virus-associated monoclonal lymphoid proliferation in an immunocompetent child. A 2-year-old male with acute otitis media presented with a right-sided facial palsy secondary to acute mastoiditis. During mastoid decompression a polypoid mass, a histologically diffuse large B cell lymphoma, was found. Staging revealed localized disease. At surgical re-exploration 5 weeks later the disease had resolved. Retrospective serological testing was consistent with an acute Epstein-Barr viral infection and in situ hybridization of the tumour tissue was positive for Epstein-Barr RNA.

Anaplastic large cell lymphoma arises in thymocytes and requires transient TCR expression for thymic egress.

Anaplastic large cell lymphoma (ALCL) is a peripheral T-cell lymphoma presenting mostly in children and young adults. The natural progression of this disease is largely unknown as is the identity of its true cell of origin. Here we present a model of peripheral ALCL pathogenesis where the malignancy is initiated in early thymocytes, before T-cell receptor (TCR) ß-rearrangement, which is bypassed in CD4/NPM-ALK transgenic mice following Notch1 expression. However, we find that a TCR is required for thymic egress and development of peripheral murine tumours, yet this TCR must be downregulated for T-cell lymphomagenesis. In keeping with this, clonal TCR rearrangements in human ALCL are predominantly in-frame, but often aberrant, with clonal TCRα but no comparable clonal TCRß rearrangement, yielding events that would not normally be permissive for survival during thymic development. Children affected by ALCL may thus harbour thymic lymphoma-initiating cells capable of seeding relapse after chemotherapy.

Identification of microRNAs From the miR-371~373 and miR-302 clusters as potential serum biomarkers of malignant germ cell tumors.

Current serum biomarkers for diagnosis and monitoring of malignant germ cell tumors (GCTs) show limited sensitivity and specificity. We previously observed that microRNAs of the miR-371∼373 and miR-302 clusters are overexpressed in all malignant GCTs, regardless of patient age, histologic subtype, or anatomic site, but are not reported to be coordinately up-regulated in other tumor types or disease states. Herein we show that levels of all 8 main members of the miR-371∼373 and miR-302 clusters were elevated in the serum of a 4-year-old boy at the time of diagnosis of yolk sac tumor. Levels returned to normal during an uneventful clinical follow-up, with kinetics similar to those of the conventional marker α-fetoprotein. We describe in detail the multiplex polymerase chain reaction protocol used to quantify serum microRNA levels, which is highly robust and reproducible. Our study indicates that miR-371∼373 and miR-302 cluster microRNAs are promising candidate biomarkers for improving disease monitoring (and potentially diagnosis) in malignant GCTs.