1 Department of Nephrology 2 Department of Oncology 3 Department of Gastroenterology University of Pediatric Clinic 4 Institute of Pathology 5 Clinic for Maxillofacial Surgery Medical Faculty Skopje R. Macedonia
Case
A 4.5-year-old boy presented with a 2-month history of enlarged submandibular lymph node, histologically shown to be compatible with normal structure. Since conventional treatment with broad-spectrum antibiotics did not induce regression, the child was referred to our clinic for further evaluation. Ultrasonography of the abdomen carried out in a paediatric ward showed bilateral renal enlargements with multiple oval sonolucent areas suggestive of cysts (Figure 1). Similar cystic lesions were detected in a pancreas. The liver exhibited normal echo-structure. The chest X-ray was normal; no mediastinal lymphadenopathy was found.
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Laboratory tests revealed SR 40/80, serum CRP was 16 mg/l, WBC 11.1x109/l, haemoglobin 11.7 g/dl, haematocrit 30%, RBC 4.5x1011/l and platelets 358x109/l. Urinary findings were without abnormalities (no proteinuria, haematuria, leukocyturia or cylindruria). Serum sodium was 139 mmol/l, potassium 4.6 mmol/l, calcium 2.46 mmol/l, phosphate 1.69 mmol/l, creatinine 39 µmol/l, urea 3.3 mmol/l, glucose 3.9 mmol/l, total protein 68 g/l, albumin 35 g/l, AST 25 U/l, ALT 22 U/l, alkaline phosphatase 160 U/l, and Hbs antigen was negative.
Family history for polycystic kidney disease was negative and abdominal ultrasonography of the child's parents and sister was found to be normal.
Question
What is the possible diagnosis?
Answer to question on preceding page
Finding multiple renal and extrarenal cysts on ultrasonography in our patient suggested the diagnosis of autosomal dominant polycystic kidney disease. Although family history and abdominal ultrasonography of the siblings were negative, the parents were under 30 years old and they might have not yet developed cystic lesions. In this context, when the child began to complain of toothache, the suspicion of a possible cystic salivary gland lesion was excluded by normal panoramic image of the mandible.
Over the next 2 weeks the child manifested a spectrum of signs and symptoms which were appearing, one after the another, with extremely dynamic rhythm and in the following order: abdominal pain, associated with an elevation of serum and urine amylase suggestive of pancreatitis, which normalized after few days; tenderness in the knee, shown to be normal on X-ray; a periodontal tumour occupied the right side of mandible, which was growing extremely rapidly and was followed by displacement of lower molars; low-grade pyrexia and worsening of general condition.
Phase scintigraphy of the craniofacial skeleton detected pathological accumulations in the right mandible and in the right occipital-temporal region. Pathological accumulation with low intensity was also detected in the diaphysis of the right tibia. Abdominal CT scan showed bilateral multiple renal masses with characteristic homogeneous attenuation and low contrast enhancement (Figure 2). Two hypoattenuating masses were present in the pancreas, one in the head and the other in the body. There was no evidence of involvement of other abdominal organs and lymph nodes. Bone marrow aspiration and spinal puncture were normal. Histopathological examination of the periodontal tumour revealed neoplastic tissue, with typical starry sky pattern (Figure 3
). On immunohistochemical staining, a positive result for CD 20, CD 79 A as well as surface IgM were found. The finding was conclusive with a diagnosis of Burkitt type lymphoblastic lymphoma.
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Discussion
Disease confined to the abdomen has been observed in 50% of patients with Burkitt lymphoma at presentation, presumably as bowel or mesenteric tumours [1]. Renal involvement is detected in only 38% of all patients undergoing routine computed tomography (CT) staging for lymphoma [2,3]. Usually, renal lymphoma is a manifestation of disseminated disease and is asymptomatic [3]. Often an unanticipated diagnosis is made at imaging [3]. Primary renal lymphoma has been described in the literature but is rare [4,5]. Detection of renal involvement in patients with lymphoma is vital, whether the kidney is the primary site or a site of disseminated involvement.
Several imaging options exist for the evaluation of renal involvement by lymphoma. These include i.v. pyelography (IVP), ultrasonography (US), nuclear magnetic resonance (NMR) imaging and CT. Renal lymphoma is usually hypoechoic at US, a finding that reflects tissue homogenicity [3]. Typical CT patterns in renal lymphoma include single and multiple masses, invasion from contiguous retroperitoneal disease, perirenal disease, and diffuse renal infiltration [3,6]. An atypical CT pattern may also be encountered and hence pose a diagnostic challenge. In general, the CT diagnosis of renal lymphoma is not difficult because most such patients have an already established diagnosis of lymphoma.
Notes
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References