|Year : 2019 | Volume
| Issue : 1 | Page : 10-12
Congenital mesoblastic nephroma in a premature neonate with initial presentation of hematuria – A case report with review of literature
Ipsita Dhal1, Goutami Dasnayak2, Swati Saxena1
1 Department of Pathology, Oncquest Laboratories, New Delhi, India
2 Department of Pathology, Kalinga Institute of Medical Sciences, Bhubaneswar, Odisha, India
|Date of Web Publication||3-May-2019|
Dr. Swati Saxena
Department of Pathology, Oncquest Laboratories, New Delhi
Source of Support: None, Conflict of Interest: None
Congenital mesoblastic nephroma (CMN) is a rare tumor of infancy and consists of 3%–10% of cases among all the pediatric renal tumors. Histologically, it can be classic, cellular, and mixed subtypes, with the cellular variant being difficult to differentiate from Wilms tumors and more aggressive. In this report, macroscopic hematuria was noticed first, and a right renal mass was detected in a 32-week-old premature female neonate, who was born to a 30-year-old woman by emergency cesarean section. Nephrectomy was performed, and histopathological examination of the operated specimen revealed features of cellular variant of CMN.
Keywords: Congenital mesoblastic nephroma, hematuria, nephrectomy, premature neonate
|How to cite this article:|
Dhal I, Dasnayak G, Saxena S. Congenital mesoblastic nephroma in a premature neonate with initial presentation of hematuria – A case report with review of literature. Oncol J India 2019;3:10-2
|How to cite this URL:|
Dhal I, Dasnayak G, Saxena S. Congenital mesoblastic nephroma in a premature neonate with initial presentation of hematuria – A case report with review of literature. Oncol J India [serial online] 2019 [cited 2019 May 19];3:10-2. Available from: http://www.ojionline.org/text.asp?2019/3/1/10/257617
| Introduction|| |
Neonatal renal tumors are generally rare comprising 2.5%–7% of all perinatal tumors. However, congenital mesoblastic nephroma (CMN) is the most common. The CMN represents approximately 3%–10% of all pediatric renal tumors., Usually, CMN has two histological subtypes, i.e., classic and cellular, with the classic type being the most benign nature with better prognosis. Whereas, cellular variant is aggressive in nature with recurrence and distant metastases have been reported. A third histological subtype of mixed variant has also been identified showing features of both classical and cellular variants. Herein, we report a case of cellular variant of CMN in a 32-week preterm newborn with a maternal history of hypertension and polyhydramnios in the neonatal period.
| Case Report|| |
A 30-year-old gravida 2/para 2 female presented to the emergency unit of Department of Obstetrics and Gynaecology with a chief complaint of pain abdomen for which she was evaluated and diagnosed with polyhydramnios on prenatal ultrasonography (USG) and hypertension. She had a history of undergoing cesarean section. Emergency cesarean section was performed on account of both polyhydramnios and a previous cesarean section, and a 32-week-old preterm female neonate was born. The infant was apneic, cyanotic, and bradycardic just after birth and was resuscitated successfully. On the 1st day of infant life, it was noticed with macroscopic hematuria, and physical examination showed a palpable right flank mass occupying almost the whole of the right side of the abdomen. She was admitted to the neonatal ICU. Serum creatinine, blood urea nitrogen, and serum electrolytes were within normal limits.
Abdominal USG showed a 11.0 cm × 9.0 cm heterogeneous solid mass involving the right kidney area. Computed tomography scan showed a large hypodense mass with heterogeneous enhancement arising from the right kidney (upper and mid pole) without any renal vein defect or lymphadenopathy [Figure 1]. With the above radiological findings, Wilms tumor was suspected.
|Figure 1: Postcontrast computed tomography scan (coronal view) shows a large hypodense mass with heterogeneous enhancement of the right kidney|
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After stabilizing the cardiorespiratory status, the newborn underwent an exploration laparotomy at the age of 4 weeks. Radical nephrectomy was performed for the right renal mass, and the sample was sent for histopathology. Gross examination showed a solid renal tumor weighing approximately 500 g and measuring 10.5 cm × 9 cm × 7.5 cm. At cross-sectioning, the kidney was almost entirely occupied by a tumor lesion, grayish-white in color and granular appearance with extensive areas of necrosis and hemorrhage [Figure 2]a and [Figure 2]b. Histologically, the tumor was characterized by ovoid-to-spindle cells, with moderate nuclear pleomorphism and mild-to-moderate mitotic activity, infiltrating the surrounding renal parenchyma, perirenal fat, and renal sinuses [Figure 3]a and [Figure 3]b. However, the renal pelvis, ureter, and suprarenal glands were not involved; no vascular invasion was seen.
|Figure 2: (a) Gross picture of right renal mass shows solid ovoid tumor with smooth lobulated surface, measuring 10.5 cm × 9 cm × 7 cm. (b) Cross-section is solid, grayish-white in color with extensive areas of necrosis and hemorrhage|
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|Figure 3: Microsection showing (a) tumor composed of interlacing fascicles of spindled cells entrapping renal glomeruli and tubules (H and E, ×10) and (b) showing spindle-shaped tumor cells with bipolar cytoplasmic processes and bland nuclear appearances and moderate mitotic activity (H and E, ×40)|
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Immunohistochemical examination (IHC) was performed for the diagnostic confirmation. The neoplastic cells showed positive immunoreactivity for vimentin [Figure 4]. There was no reactivity for desmin, actin, keratin, or S-100 protein. Thus, the diagnosis of CMN and cellular variant was made. The patient was on regular follow-up and found to be disease free at 16 months of follow-up.
|Figure 4: Photomicrograph showing positive reactivity to vimentin on immunohistochemical examination (×40)|
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| Discussion|| |
CMN is a rare renal tumor and commonly presents within the first 3 months of life. However, it is the most common diagnosed renal neoplasm in newborn and young infants consisting 18% of renal tumors within the first 7 months of life. Bolande et al. reported the first case of CMN in 1967 as a benign stromal neoplasm of infancy. CMN may be associated with polyhydramnios, and prematurity and pregnancies complicated by polyhydramnios may result in preterm deliveries in up to 22% of cases. In the present case, preterm delivery was done in view of severe polyhydramnios and history of a previous cesarean section complicating undetected CMN.
CMN is detected on routine prenatal USG as early as 26 weeks. Palpable abdominal mass is the most common clinical manifestation followed by others such as hypertension, hematuria, polyuria, and hypercalcemia., Saurabh et al. reported a case of CMN with macroscopic hematuria as the initial presentation without any palpable abdominal mass. In our case of CMN, the patient had a palpable abdominal mass with macroscopic hematuria in the 1st day of his life.
The differential diagnosis of a neonatal abdominal mass includes CMN, Wilm's tumor, rhabdoid tumor, neuroblastoma, clear cell sarcoma of the kidney, and renal cell carcinoma. Only less than 2% of Wilms tumor occur in younger than 3 months of age group, and the presence of vascular infiltration and pulmonary metastasis favors more toward Wilms tumors. Clear cell sarcomas and rhabdoid tumors are very rare findings, especially in infants.
Prenatal ultrasound is helpful because of the majority of cases being diagnosis in the perinatal period, and it can lead to polyhydramnios in mother and premature birth as in our case. Hypertension and hypercalcemia are the other associated features., A concentric hyperechoic and hypoechoic ring patterns surrounding the tumor is the USG finding in classic type of CMN, and a large, uniform, soft-tissue mass with minimal predominant peripheral enhancement is the characteristic appearance. Whereas, tumors with multiple cystic mass, necrosis, and foci of hemorrhage are the findings of cellular CMN.
CMN is of three histological variants such as classic, cellular, and mixed. On gross appearance, classic CMNs are solid tumors with a whorled, coarsely trabeculated cut surface. Whereas, cellular variant shows soft, fleshy masses, often with multicystic areas of gross hemorrhage or clear fluid accumulation.
Microscopically, the classic form is predominantly solid and unencapsulated with presence of fusiform spindle cells, rare mitoses, and absence of necrosis. The lesion is morphologically identical to infantile fibromatosis of the renal sinus. The cellular variant is identical to infantile fibrosarcoma and is characterized by proliferation of spindle cells with minimal intervening stroma, high cellularity, increased nuclear-to-cytoplasm ratio, a high mitotic rate, necrosis, and hemorrhage. Such hemorrhage findings may be related to gross hematuria presentation as seen in our case. Due to such aggressive pathological features, cellular variant is more aggressive with local recurrence, and distant metastases have been reported. The mixed variant consists of areas of low and high cellularity. The translocation t (12;15) (p13;q25) that gives rise to an ETV6-NTRK3 gene fusion encoding a chimeric tyrosine kinase protein is detected in most cellular CMNs. This translocation is absent in the classical variant.
On IHC studies, CMN shows feature of myofibroblastic differentiation. Reported literatures showed positive reactivity of vimentin and muscle-specific actin in cellular variant of CMN. Anunobi et al. reported positive reactivity of vimentin for classic variant of CMN. Durham et al. reported cytoplasmic reactivity for vimentin, desmin, pan muscle actin (HHF-35), and alpha-smooth muscle actin but nonreactive for keratin (AE1/AE3), epithelial membrane antigen, and S-100 protein.
Surgical treatment is the adequate first-line therapy in CMN, and complete surgical resection is the primary objective. The CMN is usually treated with radical nephrectomy, which reduces the risks of local recurrence. Classic subtype can be treated with wide surgical excision alone, whereas cellular subtype may require adjuvant chemotherapy. Recurrences are usually occurred in the 1st year, particularly for the cellular CMNs. Metastasis to the lungs, liver, and brain and local recurrences are very rare. The cases diagnosed within the first 7 months of life have 5-year event-free and overall survival rates of 94% and 96%, respectively.
| Conclusion|| |
In the present case, prenatal diagnosis of renal tumor was missed precluding antenatal counseling of the parents on the vital role of prenatal ultrasound in diagnosing such potential CMN associated with polyhydramnios. Regular follow-up is important in cellular variant, especially for the 1st year after surgery to look for possible recurrence.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/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.
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Conflicts of interest
There are no conflicts of interest.
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