Recurrent extrarenal Teratoid Wilms tumor in sacrococcygeal region of children after initial surgery: A rare case

Abstract

Teratoid Wilms tumor is a very rare tumor, about 70 cases have been reported worldwide. Extrarenal teratoid Wilms tumor is even less common. We reported a child with sacrococcygeal teratoid Wilms tumor who was diagnosed with teratoma at the time of the initial operation and relapsed shortly after the operation; we followed up for nearly two years after the second operation with no tumor recurrence or metastasis. This case tells clinicians that the diagnosis of extrarenal teratoid Wilms tumor needs to be careful, and although the prognosis of the disease is good, the premise is complete surgical resection.

Highlights

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Extrarenal TWT is a very rare tumor.
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This case is a child with recurrent extrarenal TWT after initial surgery.
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There was no recurrence after reoperation.
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Extrarenal TWT has a good prognosis, but it is important to ensure that the surgical resection is clean.

1 Introduction

Wilms’ tumor (WT) is the most common malignant kidney tumor in children, accounting for approximately 90 % of all renal tumors in this population. Teratoid Wilms’ tumor (TWT), a variant of WT, was first proposed by Variend et al. in 1984 and is characterized by the presence of numerous heterologous components. Currently, there are limited reports on TWT globally, with approximately 70 cases documented, and extrarenal TWT is even rarer. We report a case of recurrent TWT in the sacrococcygeal region after the first operation, and review the literature to discuss its clinical characteristics, so as to provide some experience for clinicians to improve their understanding of extrarenal TWT.

2 Case presentation

A female infant, aged 3 months and 13 days, was admitted to the hospital due to a sacrococcygeal mass that had been present for over 3 months. The patient was identified with a sacrococcygeal mass at birth and underwent resection of the lesion on November 4, 2022. Postoperative pathology revealed a mature cystic teratoma. One month after discharge, a follow-up ultrasound showed that the sacrococcygeal mass had reappeared; however, the child exhibited no discomfort, such as abdominal pain, constipation, or low back pain. Subsequently, the patient was readmitted to our hospital. There was no family history of the disease. Computed tomography (CT) conducted at our hospital on February 16, 2023 indicated that the center of the lesion was located on the left side of the midline, with a maximum cross-section measuring approximately 120 × 76 mm. The upper edge of the lesion reached the level of the presacrum and the L5 vertebral body, while the boundary with the caudal vertebra was indistinct. The lower edge of the lesion extended to the distal subcutaneous area of the left gluteal fissure, involving the bilateral gluteus maximus and gluteus medius muscles ( Fig. 1 ). The rectum, adjacent intestine, and uterus were significantly displaced anteriorly, and a teratoma was suspected. Alpha-fetoprotein (AFP) was measured at 73.03 ng/ml and Neuron-specific enolase (NSE) at 33.09 μg/ml, with the remainder of the test results being unremarkable. Subsequently, a second resection of the sacrococcygeal tumor was performed under general anesthesia. During the procedure, it was observed that the tumor’s boundary was unclear, lacking a complete capsule, and there was evidence of invasion into the coccyx. Postoperative pathological results indicated a sacrococcygeal teratoma with Wilms tumor components (extrarenal teratoma-like Wilms tumor). Microscopically, the tumors consisted of mature teratoma elements, including fat, fibrous connective tissue, mucinous epithelium, pancreatic tissue, and mature cartilage, with some elements arranged in an organoid pattern. Wilms tumor, primarily of the epithelial type, was identified in an area measuring 7 mm × 6 mm. Immunohistochemistry: Wilms tumor components WT1 (+), PAX8 (+), CD56 (+), VIM (weak +), Syn (−), CgA (−), INSM1 (−), SSTR2 (−), PCK (−), EMA (−), CK8/18 (−), CD99 (−), SALL4 (−), OCT3/4 (−), CD57 (−), Braf(V600E) (-, positive control +), AFP (−), α-inhibin (−), SF-1 (−), Calretinin (−), NF (−), ER (SP1) (-, positive control +), TTF-1 (−), TG (−), CK7 (−), CK20 (−), Villin (−), CDX-2 (−), SATB2 (−), Desmin (−), MyoD1 (−), Myogenin (−), P53 (scattered +, wild-type), Ki-67 (LI about 15 %); (coccyx) fibroadipose tissue and mature cartilage tissue were observed under the microscope, and other special features were not seen( Fig. 2 ). Postoperative chemotherapy (vincristine sulfate and actinomycin) was given. One month after surgery, AFP was 26.95 ng/ml, and NSE was normal. Two years after the operation, the patient was healthy, and no tumor recurrence was found in the sacrococcygeal region or other parts of the body.