Cushing's disease due to a giant pituitary adenoma in early infancy: CT and MRI features

Clinical Outcomes and Complications of Pituitary Blastoma

CONTEXT

Pituitary blastoma is a rare, dysontogenetic hypophyseal tumor of infancy first described in 2008, strongly suggestive of DICER1 syndrome.

OBJECTIVE

This work aims to describe genetic alterations, clinical courses, outcomes, and complications in all known pituitary blastoma cases.

DESIGN AND SETTING

A multi-institutional case series is presented from tertiary pediatric oncology centers.

PATIENTS

Patients included children with pituitary blastoma.

INTERVENTIONS

Genetic testing, surgery, oncologic therapy, endocrine support are reported.

OUTCOME MEASURES

Outcome measures included survival, long-term morbidities, and germline and tumor DICER1 genotypes.

RESULTS

Seventeen pituitary blastoma cases were studied (10 girls and 7 boys); median age at diagnosis was 11 months (range, 2-24 months). Cushing syndrome was the most frequent presentation (n = 10). Cushingoid stigmata were absent in 7 children (2 with increased adrenocorticotropin [ACTH]; 5 with normal/unmeasured ACTH). Ophthalmoplegia and increased intracranial pressure were also observed. Surgical procedures included gross/near-total resection (n = 7), subtotal resection (n = 9), and biopsy (n = 1). Six children received adjuvant therapy. At a median follow-up of 6.7 years, 9 patients were alive; 8 patients died of the following causes: early medical/surgical complications (n = 3), sepsis (n = 1), catheter-related complication (n = 1), aneurysmal bleeding (n = 1), second brain tumor (n = 1), and progression (n = 1). Surgery was the only intervention for 5 of 9 survivors. Extent of resection, but neither Ki67 labeling index nor adjuvant therapy, was significantly associated with survival. Chronic complications included neuroendocrine (n = 8), visual (n = 4), and neurodevelopmental (n = 3) deficits. Sixteen pituitary blastomas were attributed to DICER1 abnormalities.

CONCLUSIONS

Pituitary blastoma is a locally destructive tumor associated with high mortality. Surgical resection alone provides long-term disease control for some patients. Quality survival is possible with long-term neuroendocrine management.

Germline and somatic DICER1 mutations in a pituitary blastoma causing infantile-onset Cushing's disease

CONTEXT

Pituitary blastoma causing Cushing's syndrome in infancy is very rare, and its molecular pathomechanism is not well understood.

OBJECTIVE

Our objective was to identify genetic changes of a pituitary blastoma causing infantile-onset Cushing's syndrome in a Thai girl without a family history of cancers.

METHODS

Genomic DNA from both leukocytes and tumor tissues was used for whole-exome sequencing (WES) and Sanger sequencing of DICER1. The cDNA reverse-transcribed from RNA extracted from both leukocytes and tumor tissues was used for Sanger sequencing, quantitative real-time PCR (qRT-PCR), and pyrosequencing of DICER1.

RESULTS

WES of leukocytes identified a novel heterozygous c.3046delA (p.S1016VfsX1065) mutation in the DICER1 gene. WES of the tumor tissues detected the same frameshift germline mutation and another novel somatic missense c.5438A→T (p.E1813V) mutation. Both mutations were validated by Sanger sequencing. Quantitative real-time PCR revealed that the DICER1 mRNA levels of the tumor tissues were 54% compared with those of her leukocytes. Pyrosequencing showed that the deletion allele constituted 12% and 0% of the DICER1 cDNA of the proband's leukocytes and tumor tissues, respectively.

CONCLUSION

Our study extends the phenotypic and mutational spectrum of DICER1 mutations to include infantile-onset Cushing's disease and 2 novel mutations. Loss of function of both DICER1 alleles appears to be crucial to initiate tumor development.

Pituitary blastoma: a pathognomonic feature of germ-line DICER1 mutations

Individuals harboring germ-line DICER1 mutations are predisposed to a rare cancer syndrome, the DICER1 Syndrome or pleuropulmonary blastoma-familial tumor and dysplasia syndrome [online Mendelian inheritance in man (OMIM) #601200]. In addition, specific somatic mutations in the DICER1 RNase III catalytic domain have been identified in several DICER1-associated tumor types. Pituitary blastoma (PitB) was identified as a distinct entity in 2008, and is a very rare, potentially lethal early childhood tumor of the pituitary gland. Since the discovery by our team of an inherited mutation in DICER1 in a child with PitB in 2011, we have identified 12 additional PitB cases. We aimed to determine the contribution of germ-line and somatic DICER1 mutations to PitB. We hypothesized that PitB is a pathognomonic feature of a germ-line DICER1 mutation and that each PitB will harbor a second somatic mutation in DICER1. Lymphocyte or saliva DNA samples ascertained from ten infants with PitB were screened and nine were found to harbor a heterozygous germ-line DICER1 mutation. We identified additional DICER1 mutations in nine of ten tested PitB tumor samples, eight of which were confirmed to be somatic in origin. Seven of these mutations occurred within the RNase IIIb catalytic domain, a domain essential to the generation of 5p miRNAs from the 5' arm of miRNA-precursors. Germ-line DICER1 mutations are a major contributor to PitB. Second somatic DICER1 "hits" occurring within the RNase IIIb domain also appear to be critical in PitB pathogenesis.

Cushing disease in a toddler: not all obese children are just fat

Cushing disease is exceedingly rare in children, especially in those under the age of 2 years. This case report describes an 18-month-old female child who presented with morbid obesity, decreased linear growth, and reversal of developmental milestones. Her diagnosis was delayed; however, she was successfully treated by surgical excision of the microadenoma. This was followed by resolution of signs and symptoms of Cushing syndrome. Although the patient's hypertension resolved, linear growth improved and development began to progress, she is still developmentally delayed and now has hypopituitarism. Review of this case, as well as a handful of other cases of infantile Cushing disease in the literature, suggests that features such as hypertension and slowed linear growth, which are rare in nutritional causes of obesity in infants, can help identify this rare, but life-threatening, illness among an increasing number of overweight infants.

Giant pituitary macroadenoma at the age of 4 months: case report and review of the literature

CASE REPORT

Adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma is extremely rare. Only five cases are reported in the literature to date. We report the youngest patient of Cushing's disease due to ACTH-secreting pituitary macroadenoma at the age of 4 months. The patient presented with cushingoid facial features, hypertension and optic atrophy. Serum cortisol level was 97 microg/dl, with increased secretion of urinary free cortisol; plasma ACTH level was 353 pg/ml. Magnetic resonance imaging of the brain showed a large contrast-enhancing solid mass sitting in the sellar region, with suprasellar and lateral extension. Surgical resection was done, and immunohistochemistry confirmed the diagnosis of ACTH-secreting pituitary adenoma. Postoperatively, the patient died of disseminated intravascular coagulopathy.

CONCLUSION

Cushing's disease due to ACTH-secreting pituitary macroadenoma is a possible diagnosis in early infancy. This report, along with five previously reported cases in the literature, revealed a poor surgical outcome. This surgical morbidity is possibly attributed to difficult peroperative hemostasis due to vasculopathy in Cushing's disease, which leads to excessive blood loss, adverse hemodynamic changes, myocardial dysfunction and disseminated intravascular coagulopathy.

Pituitary macroadenoma and Cushing's disease in pediatric patients: patient report and review of the literature

Cushing's syndrome in pediatric patients has been rarely reported and most of the cases are due to adrenal tumors. When the etiology is an ACTH-secreting pituitary adenoma, most often it is a microadenoma. We report on a 9 year-old girl with an ACTH-secreting macroadenoma, whose surgical removal through transsphenoidal approach was extremely difficult due to invasion of the cavernous sinus as well as adjacent structures. After two surgical approaches and stereotactic radiotherapy, she still suffers from the deleterious effects of hypercortisolism, especially marked osteoporosis with vertebral collapse, which interferes with her walking and causes excruciating pain. Two months after the radiotherapy, we still had doubts about the prognosis regarding the persistence of the hypercortisolism. From six months on, her general health started improving, she lost weight, the backache disappeared and her cortisol level returned to normal.