Pelvic Lipoblastoma with Extension into Ischiorectal Fossa and Abdominal Lipoblastoma - Complete Excision by Laparoscopy in Children - A Report of Two Cases.

Lipoblastoma is a relatively rare tumor that occurs in infancy and early childhood which arises from embryonic fat. It occurs mostly in trunk and extremities, but abdomen and pelvic lipoblastomas are rare. It presents as a mass with or without mass effect. Computed tomography/magnetic resonance imaging of the abdomen with pelvis is the investigation of choice. We present two cases of pelvic lipoblastoma with extension in ischiorectal fossa and the intra-abdominal lipoblastoma which were excised completely by laparoscopy. We are reporting these cases because of rarity of the disease and feasibility of complete laparoscopic excision. Copyright:

INTRODUCTION

Lipoblastoma is a benign soft tissue solid tumor composed of immature embryonal fat tissue first reported by Jaffe in 1926. It is a relatively rare tumor that occurs in infancy and early childhood. These are primarily located in the soft tissues of the trunk and extremities, and are rarely reported in the buttock, perirectal area, and abdomen. Only eight perineal lipoblastoma cases are reported in the literature.[1] Intraperitoneal lipoblastoma is also extremely rare and comprises only 7% of these tumors.[2] The exact etiology is not known. It can present with mass or mass effect on adjacent organs. Solid omental masses can mimic an acute abdomen because of bleeding or intestinal infarction, requiring emergent surgery.[3] Abdominal contrast-enhanced computed tomography (CECT) scan is the diagnostic study of choice in abdominal tumors. CECT scan usually shows a uniform, well-circumscribed fat-density mass and can identify the primary tumor site. It can also indicate compression on adjacent organs.[4] Magnetic resonance imaging (MRI) scan is the investigation of choice in pelvic tumors to differentiate from other soft tissue tumors of ischiorectal fossa.[5] Most cases of intraperitoneal tumors can be cured by surgery.[6]

MATERIALS AND METHODS

Case 1

A 9-year-old male child presented with constipation for 1 year, not relieved by laxatives, and the parents recently noticed a swelling in the left perineal region. On abdominal examination, there was a suprapubic mass with minimal mobility. On perrectal examination, a firm mass was felt in the presacral region more onto the left ischiorectal fossa. No neurological deficits were noted. MRI of the abdomen and pelvis [Figure 1] revealed a mass 13.5 cm × 9 cm × 7.1 cm in size predominantly containing fat within the pelvis with extension into the left ischiorectal fossa suggestive of lipoblastoma/lipoma. After preoperative workup, the child was taken up for surgery. He was placed in lithotomy position exposing both abdomen and perineal region for abdominoperineal approach. He was planned for diagnostic laparoscopy ± laparotomy. We started the dissection with opening of pelvic peritoneum, continued in the avascular plane to excise completely a dumbbell-shaped tumor from the left ischiorectal fossa [Figure 2]. To our surprise, we could completely remove the tumor by laparoscopy not requiring perineal incision. The specimen was retrieved through Pfannenstiel incision. Gross findings of lobulated swelling were noted. Histopathology was consistent with lipoblastoma that is lipoblasts and mature adipocytes in lobular pattern separated by paucicellular fibrous septa [Figure 3]. Postoperative period was uneventful. On 3-year follow-up, the child is doing well without recurrence of the lesion.

Figure 1

Magnetic resonance imaging pelvis sagittal section: Tumor occupying presacral space and compressing bladder neck and rectum (black arrow)

Figure 2

Ports site and retrieved specimen (labeled on the image)

Figure 3

Histopathology of lipoblastoma - lipoblasts and mature adipocytes in lobular pattern separated by paucicellular fibrous septa

Case 2

An 8-year-old male child was incidentally detected to have intra-abdominal mass on ultrasound while being evaluated for pyrexia of unknown origin. Further, he underwent CECT scan of the abdomen for which revealed 10 cm × 8 cm × 5.5 cm size fat dense lesion suggestive of lipoblastoma. After preoperative workup, the child was planned for diagnostic laparoscopy ± laparotomy. Three laparoscopy ports were placed and dissection was started in the avascular plane. We could completely excise the tumor which was arising from the right suprarenal region [Figure 4]. The child was kept nil orally for 36 h and started on feeds which was tolerated well. He got discharged home on 3rd postoperative day. The specimen was retrieved piecemeal after placing in a specimen bag. Histopathology findings were consistent with lipoblastoma. Postoperative period was uneventful. On 3-year follow-up, the child is doing well without recurrence of the lesion.

Figure 4

Laparoscopic view of intra-abdominal lipoblastoma

DISCUSSION

Lipoblastoma is a rare tumor which arises from embryonic fat. More than 90% of lipoblastoma occurs in those below 3 years of age.[7] It occurs mostly in trunk (10%–60%) and extremities (40%–45%);[7] however, abdomen and pelvic lipoblastomas are rare. Abdominal tumors are usually detected incidentally, while pelvic tumors can present with mass effects such as constipation or urinary disturbance. In our series, both the patients are above 8 years old.

In our case 1, the child presented with chronic constipation and later with appearance of swelling in the perineum. We stress the importance of perrectal examination in a child with constipation to ascertain the possibility of presacral masses.

Case 2 was an incidental finding.

Ultrasound abdomen is the first-line investigation, but CECT scan/MRI is required to know the origin of the lesion and to differentiate from other soft tissue tumors. Unless the radiological appearances are diagnostic, percutaneous biopsy is recommended.[8] In histologically borderline cases, tumor karyotype establishes an accurate diagnosis.[2] Complete surgical excision is the treatment.[6] However, there is a 14% to 20% chance of local recurrence usually because of incomplete excision.[9] In both cases, we could remove the tumor completely by the laparoscopic method. The first case was challenging as it was a dumbbell-shaped tumor extending into the left ischiorectal fossa. We were prepared to do abdominoperineal approach,[10] but to our surprise, we could completely remove it by laparoscopic method. Immediate postoperative recovery was uneventful. No recurrence after 3-year follow-up. Recurrence has been reported to occur after as long as 7 years postoperatively. Hence, a follow-up period beyond 3–5 years is recommended.[211]

CONCLUSION

Even though lipoblastomas in abdomen and pelvic region are rare, a high index of suspicion is necessary to diagnose one. We highlight the importance of perrectal examination in a case of constipation to avoid missing presacral masses. Large tumors in the pelvis with extension into ischiorectal fossa and abdomen can be removed laparoscopically. As it gives better vision and easy dissection in depth, we recommend that to consider laparoscopic removal for such large tumors. In view of tumor extending to ischiorectal fossa, be prepared for perineo abdominal approach. Counseling regarding postoperative neurogenic bladder/bowel is a must.

Declaration of patient consent

The authors certify that they have obtained all appropriate patients' consent for publishing these case reports, including consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.