Lipoblastomatosis combined with intestinal neuronal dysplasia

Archives of Pathology & Laboratory Medicine,  Feb 1998  by Huang, Chao-Cheng,  Ko, Sheung-Fat,  Chuang, Jiin-Haur,  Chen, Wei-Jen

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* We report the case of a male infant with multifocal lipoblastomatosis and intestinal pseudo-obstruction for whom the pathologic findings of rectal biopsy were consistent with intestinal neuronal dysplasia. Lipoblastomatosis is a benign neoplasm of human fetal white adipose tissue that mainly occurs in infants and children. Intestinal neuronal dysplasia is a disorder that clinically mimics Hirschsprung's disease and that is pathologically characterized by parasympathetic hyperganglionosis of the enteric nervous system. To our knowledge, the combination of lipoblastomatosis and intestinal neuronal dysplasia has never been documented, and the gene mutations involved are completely different. In this case, therefore, we postulate that intestinal neuronal dysplasia may be secondary to either compression of the nerve tract or inhibition of bowel movement due to lipoblastomatosis.

(Arch Pathol Lab Med. 1998;122:191-193)

Lipoblastoma and lipoblastomatosis are rare benign tumors of adipose tissue, usually occurring in infants and young children. Although most of the reported cases involve the extremities, the disease can arise almost anywhere in the soft tissue.l Lipoblastomatosis with intraspinal involvement, however, is extremely rare.2

Intestinal neuronal dysplasia (IND), first described by Meier-Ruge3 in children who presented in a manner resembling Hirschsprung's disease, is classified into two distinct subtypes, types A and B. Intestinal neuronal dysplasia A is characterized by hypoplasia or aplasia of the sympathetic innervation of the intestinal wall; IND B is defined as abnormalities in the development of the intestinal submucosal plexus.4 Intestinal neuronal dysplasia associated with other intestinal disorders, such as Hirschsprung's disease, anorectal malformations, and chronic proctitis, have been well documented.4,5

We report a case of lipoblastomatosis involving multiple areas, including neck, back, abdominal wall, inguinal area, retroperitoneum, and lower spinal canal. The patient clinically presented with intestinal pseudo-obstruction, and rectal biopsy produced a pathologic picture consistent with IND B. The implications of the concurrent lipoblastomatosis and IND are discussed.

REPORT OF A CASE

An 8-month-old male infant delivered by cesarean section had had abdominal distension and constipation since birth. Physical examination revealed loose anal tone and a soft subcutaneous mass, presumably a lipomatous lesion, over the lower back when the child was 4 months old. The rectoanal inhibiting reflex was positive on manometer examination. Plain abdominal radiograph showed excessive bowel gas in the abdomen, but no apparent obstruction. Barium meal small bowel study and barium enema revealed poor motility of the small intestinal loops and colon. No evidence of intestinal obstruction or megacolon was found. The patient then underwent spinal magnetic resonance imaging examination, which exhibited excessive lipomatous proliferation in lower back muscle, retroperitoneum, and lower spinal canal, but no evidence of spinal dysrhaphia was found. Suction biopsy of the rectal mucosa showed increased acetylcholinesterase activity in the lamina propria, but no submucosal tissue was included in the tissue for evaluating the presence of ganglion cells.

Despite conservative treatment, the patient continued to suffer from intermittent fever and alternate constipation, vomiting, and diarrhea. Physical examination 4 months later revealed cachectic appearance with bulging masses in the neck and buttock, marked abdominal distention, inguinal mass, and left hydrocele. Followup chest and abdominal magnetic resonance imaging delineated excessive fatty tissue involving the neck, supraclavicular region, back, abdominal wall, gluteal muscle, mesentery, retroperitoneum, bilateral inguinal areas, perirectal region, and epidural region of the lower thoracic to sacral level (Fig 1). Therefore, the soft tissue masses from right neck, supraclavicular, flank, and bilateral inguinal areas were excised. Left hydrocelectomy and rectal wall biopsy at 3.5 cm proximal to the anal verge were also performed. Unfortunately, the infant died of cachexia and septic shock 6 days after surgery. Permission for autopsy was not obtained.

PATHOLOGIC FINDINGS

The specimens received were several lipomatous masses. The largest mass that was excised from the left inguinal area measured 6.0 x 4.5 x 2.0 cm. Grossly, some of the masses were well circumscribed, lobulated, and soft, but the tissues from the neck and the supraclavicular areas were poorly circumscribed. The external surfaces of all the tissues were light yellow to creamy white and glistening. The cut surfaces were solid and homogeneous, and had no apparent necrosis or hemorrhage.

Microscopically, the fatty masses were lobulated and surrounded by thin fibrous strands with slender fibrous connective tissue septa. The septa were rich in capillaries and venules. The masses from bilateral inguinal areas were mainly composed of mature adipocytes and lipoblasts (Fig 2, A). The latter exhibited a multivacuolated cytoplasm and centrally located, indented nuclei. Some clusters of signet-ring-like cells were noted in the periphery (Fig 2, B). These cells were negative for periodic acidSchiff and mucicarmine stains, representing monovacuolated lipoblasts. In addition, a few clusters of small round cells were present, which possessed finely granular cytoplasm and slightly atypical nuclei. Nuclear pleomorphism was not evident, and mitotic figures were rarely found. Primitive mesenchymal cells were not identified. The right neck, supraclavicular, and flank masses, however, were almost entirely composed of lobules of mature adipocytes, with the exception of some clusters of monovacuolated lipoblasts at the periphery of the supraclavicular mass.