Prepared by Sam T. Auringer, MD; T. David Cox, MD; and
Thomas E. Sumner, MD, Department of Radiology, Wake Forest
University Baptist Medical Center, Winston-Salem, NC.
CASE SUMMARY
A 3-year-old girl presents with refusal to walk, weakness, leg
cramps, and a 20-month history of chronic diarrhea. Initial
laboratory workup revealed a significant hypokalemia. Subsequent
diagnostic imaging studies appear in figures 1, 2, and 3.
DIAGNOSIS
Thoracic ganglioneuroma presenting with the watery diarrhea,
hypokalemia, and achlorhydria (WDHA) syndrome.
IMAGING FINDINGS
Findings indicative of a posterior mediastinal mass on plain
film and chest computed tomography (CT) scans suggest the diagnosis
of a neurogenic tumor, as 95% of pediatric posterior mediastinal
masses are of neurogenic origin. The primary differential
considerations are tumors of sympathetic ganglion origin (i.e.,
neuroblastoma, ganglioneuroblastoma, and ganglioneuroma).
1
The patient's age favored a neuroblastoma or ganglioneuroblastoma,
as ganglioneuroma tends to occur in older children. Plain film
findings of thoracic neuroblastoma include a posterior mediastinal
mass, possibly associated with ribs that are splayed or eroded or
both; calcifications; and enlarged intervertebral foramina in cases
with intraspinal extension of tumor. CT demonstrates calcification
in approximately 90% of neuroblastomas. Magnetic resonance (MR)
imaging is the test of choice for thorough evaluation of
intraspinal extension of tumor.
2
DISCUSSION
The WDHA syndrome is an unusual paraneoplastic condition caused
by excess vasoactive intestinal peptide (VIP) secretion by certain
tumors, including the
neuroblastoma-ganglioneuroblastoma-ganglioneuroma spectrum in
children and non-beta pancreatic islet cell tumors, squamous cell
tumors of lung or esophagus, cutaneous mast cell tumors, and
pheochromocytomas in adults.
3
Ganglioneuromatosis of the small intestine and pancreas, causing
hypersecretion of VIP, has been reported.
4
The WDHA syndrome has also been referred to as the vipoma syndrome,
pancreatic cholera, the watery diarrhea syndrome, and the
Verner-Morrison syndrome after its discoverers in 1958.
5
Clinically, the onset of WDHA syndrome is typically insidious and
diagnosis is often delayed for months or even years. The clinical
hallmark is an unremitting secretory diarrhea that persists despite
fasting. Diagnosis requires documentation of elevated serum VIP
levels with subsequent localization of the VIP-secreting tumor.
Surgical resection is usually curative, as it was in this case.
REFERENCES
1. Hedlund GL, Griscom NT, Cleveland RH, Kirks DR:
Respiratory system. In: Kirks DR (ed): Practical Pediatric Imaging:
Diagnostic Radiology of Infants and Children, ed 3, pp 790-792.
Philadelphia, Lippincott-Raven, 1998.
2. Abramson SJ:
Adrenal neoplasms in children. Radiol Clin North Am 35:1415-1453,
1997.
3. Grier JF:
WDHA (watery diarrhea, hypokalemia, achlorhydria) syndrome:
Clinical features, diagnosis, and treatment. South Med J 88:22-24,
1995.
4. Shulman DI, McClenathan DT, Harmel RP, et al:
Ganglioneuromatosis involving the small intestine and pancreas of a
child and causing hypersecretion of vasoactive intestinal
polypeptide. J Pediatr Gastroenterol Nutri 22:212-218, 1996.
5. Castleberry RP:
Biology and treatment of neuroblastoma. Pediatr Clin North Am
44:919936, 1997.