Expanding the clinicopathological spectrum of succinate dehydrogenase-deficient renal cell carcinoma with a focus on variant morphologies: a study of 62 new tumors in 59 patients.

Most succinate dehydrogenase (SDH)-deficient renal cell carcinomas (RCCs) demonstrate stereotypical morphology characterized by bland eosinophilic cells with frequent intracytoplasmic inclusions. However, variant morphologic features have been increasingly recognized. We therefore sought to investigate the incidence and characteristics of SDH-deficient RCC with variant morphologies. We studied a multi-institutional cohort of 62 new SDH-deficient RCCs from 59 patients. The median age at presentation was 39 years (range 19-80), with a slight male predominance (M:F = 1.6:1). A relevant family history was reported in 9 patients (15%). Multifocal or bilateral tumors were identified radiologically in 5 patients (8%). Typical morphology was present at least focally in 59 tumors (95%). Variant morphologies were seen in 13 (21%) and included high-grade nuclear features and various combinations of papillary, solid, and tubular architecture. Necrosis was present in 13 tumors, 7 of which showed variant morphology. All 62 tumors demonstrated loss of SDHB expression by immunohistochemistry. None showed loss of SDHA expression. Germline SDH mutations were reported in all 18 patients for whom the results of testing were known. Among patients for whom follow-up data was available, metastatic disease was reported in 9 cases, 8 of whom had necrosis and/or variant morphology in their primary tumor. Three patients died of disease. In conclusion, variant morphologies and high-grade nuclear features occur in a subset of SDH-deficient RCCs and are associated with more aggressive behavior. We therefore recommend grading all SDH-deficient RCCs and emphasize the need for a low threshold for performing SDHB immunohistochemistry in any difficult to classify renal tumor, particularly if occurring at a younger age.

Rare case of intussusception in an adult with acute myeloid leukemia.

Intussusception is rarely reported in adult patients with acute leukemia. We report a case of intussusception in a 29-year-old woman with acute myeloid leukemia (AML). She developed right lower quadrant pain, fever, and vomiting on day 16 of induction chemotherapy. Physical examination showed tenderness and guarding at the right lower quadrant of the abdomen. Abdominal computed tomography (CT) showed distension of the cecum and ascending colon, which were filled with loops of small bowel, and herniation of the ileocecal valve into the cecum. We proceeded to laparotomy and revealed ileocecal intussusception with the ileocecal valve as the leading point. The terminal ileum was thickened and invaginated into the cecum, which showed gangrenous changes. Right hemicolectomy was performed and microscopic examination of the colonic tissue showed infiltration of leukemic cells. The patient recovered after the operation and was subsequently able to continue treatment for AML. This case demonstrates that the diagnosis of intussusception is difficult because the presenting symptoms can be non-specific, but abdominal CT can be informative for preoperative diagnosis. Resection of the involved bowel is recommended when malignancy is suspected or confirmed. Intussusception should be considered in any leukemia patients presenting with acute abdomen. A high index of clinical suspicion is important for early diagnosis.

Primary yolk sac tumour of the urinary bladder: A case report and review of the literature.

We present a case of rare primary yolk sac tumour of the urinary bladder in adulthood. A 31-year-old female patient presented with a history of chronic ketamine abuse, which has not previously been shown to be associated with malignancy development. The final diagnosis was established only after radical cystectomy. A computed tomography (CT) scan showed paraaortic lymph node metastasis. The patient was treated with systemic chemotherapy. A review of the literature revealed that surgical excision and cisplatin-based chemotherapy remain to be the standard of care for extragonadal yolk sac tumours.

Molecular diagnosis for a fatal case of very long-chain acyl-CoA dehydrogenase deficiency in Hong Kong Chinese with a novel mutation: a preventable death by newborn screening.

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is one of the most common fatty acid oxidation defects that cause sudden unexpected deaths in infants. The death attributed to VLCAD deficiency can be prevented by early diagnosis with expanded newborn screening using tandem mass spectrometry. A favorable outcome can be achieved with early diagnosis and prompt treatment. However, such newborn screening has not yet been available in Hong Kong. We report a 2-month-old boy who succumbed 5 hours after admission with the diagnosis of VLCAD deficiency confirmed by genetic analysis performed after death. The patient was compound heterozygous for a novel splicing mutation ACADVL NM_000018.2:c.277+2T>G; NC_000017.10:g.7123997T>G and a known disease-causing mutation ACADVL NM_000018.2:c.388_390del; NP_000009.1: p.Glu130del. Family screening was performed for at-risk siblings. The rapid downhill course of the patient clearly illustrates the need of newborn screening for early diagnosis. Our patient was asymptomatic before metabolic decompensation. However, once metabolic decompensation occurred, rapid deterioration and death followed, which obviated the opportunity to diagnose and treat. The only way to save these patients' lives and improve their outcome is early diagnosis and appropriate treatment. Therefore, we strongly urge the implementation of newborn screening using tandem mass spectrometry for VLCAD deficiency and other highly treatable inborn errors of metabolism in Hong Kong.