Abstract
Primary Ewing sarcoma of the kidney is an extremely rare yet aggressive tumour. We present a 31-year-old pregnant female who presented to the emergency department with macroscopic haematuria and an ultrasound scan demonstrating a right renal mass. On magnetic resonance imaging, the lesion had features concerning for malignancy. She underwent a radical nephrectomy and was commenced on a personally tailored chemotherapy regime designed to permit healthy delivery of her baby while adequately treating her disease. This highlights an extremely rare differential for a renal mass which should be considered in rapidly growing renal tumours of a young patient.
1. Introduction
Ewing sarcoma (ES), also called primitive neuroectodermal tumour (PNET) is a rare yet lethal entity. This group of malignant tumours originates from the neuroectoderm typically in soft tissue and bone of children and young adults. Only very rarely do they present as a primary neoplasm of the kidney. Timely and correct diagnosis is critical because these tumours are highly malignant, rapidly growing and metastasize early thus carrying an often-poor prognosis. Given the scarcity of cases of ES of the kidney, optimal management is inconsistent and the diagnosis during pregnancy represents a serious and rare clinical conundrum not previously described.
Herein, we present a case of a 31-year-old pregnant female who was diagnosed with a primary Ewing sarcoma of the kidney. This case highlights the therapeutic, radiographic, and personal dilemmas surrounding the diagnosis in this setting.
2. Case presentation
A 31-year-old pregnant female was seen in the emergency department with a 3-day history of macroscopic haematuria. The haematuria was associated with intermittent colicky right sided flank pain. Her medical history was unremarkable apart from being 4 weeks pregnant with her first child. She is a non-smoker and denied occupational exposure to petroleum, textiles, or dyes.
On examination, there was no peripheral stigmata of chronic disease and she weighed 82kg. Her vitals were within normal limits, and she was afebrile. Her abdomen was soft and non-tender without palpable masses.
On investigations, haemoglobin (Hb) was 111g/L with a raised white cell count of 14.8 × 109/L. Electrolytes and renal function were normal. Beta human chorionic gonadotrophin (b-HCG) was positive at 36IU/L and a urine microscopy revealed >500 × 106 erythrocytes with 20 × 106 leukocytes without bacterial growth.
Ultra-sound (US) pelvis showed normal ovaries and no obvious intra-uterine gestation. US Kidneys, ureter, and bladder (KUB) however revealed a 6.1cm heterogenous, solid, echogenic mass with internal vascularity arising from the lower pole of the right kidney (Fig. 1).
Fig. 1.
US imaging on first presentation for haematuria. Showing 6.1 cm heterogeneous, predominantly echogenic mass with internal vascularity arising from the right renal lower pole.
Given this significant finding, the patient was admitted for monitoring of Hb and signs of bleeding. An MRI was ordered however on further discussion with the radiology department, MRI in first trimester was not yet proven to be safe and therefore the MRI was completed shortly after 11 weeks gestation which revealed an 11.6 cm lesion arising from the mid/inferior aspect of the right kidney (Fig. 2). This contained intralesional haemorrhage and fat. The differential for this appearance would be an RCC or lipid poor AML. A CT chest with pregnancy precautions showed no obvious nodules or lesions consistent with metastatic disease. Given the concerning growth rate of the lesion; a decision was made to proceed with laparoscopic radical right nephrectomy during pregnancy.
Fig. 2.
Axial cross-sectional MRI demonstrating a 11.6 cm lesion arising from the mid/inferior aspect of the right kidney. This contains intralesional haemorrhage and fat with associated hydronephrosis.
Intra-operatively, a large 12cm mass was seen projecting from the inferior aspect of the right kidney. The kidney was resected successfully without perforation and her recovery in hospital was un-eventful.
Histologically the tumour was consistent with a primary Ewing sarcoma of the kidney (Fig. 3). The tumour invaded sinus fat and segmental branches of renal vein but was clear of margins.
Fig. 3.
A) High powered histopathology demonstrates round blue non-descript cells with a focal area of necrosis. Most of the cells have fine chromatin with occasional nuclei. Morphological appearance in keeping with Ewing sarcoma. B) Nuclear positive staining with NXK2.2 is highly sensitive and specific for Ewing sarcoma. C) Low powered histopathology slide showing diffuse infiltration of tumour composed of small round blue cells growing in a diffuse pattern forming perivascular pseudo papillary structures and pseudo rosettes. Non-neoplastic kidney shows increased number of acute and chronic inflammatory cells. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
Given the patient's difficulty with fertility in the past and this being her first successful pregnancy, the priority for the patient was to deliver a healthy baby. A personally tailored regime consisting of vincristine, doxorubicin, and cyclophosphamide (VDC) was commenced at 20 weeks gestation and then after delivery, Ifosfamide and etoposide (IE) were added to the treatment regime in an attempt to control cancer progression but also give the patient the best chance of successful delivery. The patient successfully gave birth to a healthy baby and remains in remission on surveillance CT imaging 12 months following the diagnosis.
3. Discussion
Ewing sarcoma of kidney is a very rare yet ominous diagnosis most commonly affecting young people where median age at diagnosis is 27–28 years of age.1 While renal ES has been reported periodically in the literature, primary ES of the kidney requiring nephrectomy during pregnancy is yet to be described. The disease is characterised by an aggressive course where at time of diagnosis 25–50% of patients have evidence of metastatic spread.2 Unless found incidentally which is rare, presenting complaints consist of flank pain (85%), palpable mass (60%), and haematuria (37%). The differentials for renal masses are often broad and consist of both benign and malignant growths.3 Despite advances with modern imaging, no specific features on ultrasonography, CT, or MRI can confidently differentiate ES from other renal tumours and so histological diagnosis is required.
Gold standard imaging for a renal mass is a CT renal multiphase scan however in a pregnant patient, this is contra-indicated which leaves US and MRI as the two alternate options. Regarding MRI, guidelines from the Australia and New Zealand College of Radiologists pose a theoretical teratogenesis risk to the foetus due to exposure from electromagnetic fields in the first trimester. They describe theoretical risks to hearing of the foetus which may be of concern as well as potential thermal stressors. In reality however, multiple follow up studies of children scanned at multiple trimesters in utero did not demonstrate harmful effects.4
Once diagnosis is made, a multi-modal treatment regime is required consisting of surgical resection and adjuvant chemotherapy in cases of localised disease. Adjuvant chemotherapy for Ewing tumours has been described by the European Ewing tumour working initiative of national groups 1999 (EURO-EWING 99) which consists of six courses of chemotherapy (vincristine, ifosfamide, doxorubicin, and etoposide). In localised disease, surgical resection with adjuvant chemotherapy has a 5-year survival rate of up to 60%. The presence of metastatic disease at diagnosis will drop this to 10–30%.
4. Conclusion
Primary ES of the kidney is a rare and aggressive pathology. ES of the kidney in a female during the first trimester adds extra complexities to its definitive diagnosis and management and is yet to be described in the literature. A multimodal approach consisting of surgery, chemotherapy and in some cases radiation therapy are required to give the best chance of reducing recurrence.5 In our case, personal factors played a part and medical teams should work with the patient in a partnership to formulate the optimal tailored therapy.
Ethics
Consent was obtained from patient for publication of their case. Copy of consent can be obtained from author.
Funding
No funding was obtained for this case report.
Declaration of competing interest
There are no conflicts of interest to report.
References
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