Case presentation
In September 2021, a 13-year-old boy presented to the emergency
department of our medical facility complaining of fatigue and widespread
edema over the last two months. Additionally, he reported two bilateral
painless subcutaneous masses on both sides of his neck with progressive
growth over the past six months.
He was previously admitted to our center in August 2020 with generalized
edema and a preliminary diagnosis of nephrotic syndrome. At that time,
after performing an ultrasound-guided renal biopsy which showed
segmental proliferation of the mesangial and endothelial cells, the
diagnosis of FSGS was made. So, he was treated with pulse corticosteroid
therapy (methylprednisolone 10 mg/kg/day) for three days, and after
discharge, he underwent treatment with prednisolone with a dosage of 15
mg/day that was tapered by following weeks.
He also had a history of subclinical hypothyroidism. He denied a history
of alcohol consumption or smoking; his family history was
noncontributory to kidney or autoimmune diseases.
The patient’s vital signs at the time of admission were as follows:
temperature 36.9°C, pulse rate 81 beats/minute, blood pressure 131/82 mm
Hg, respiratory rate 17 breaths/minute, and oxygen saturation 98% on
room air.
On examination, two non-tender, poorly mobile masses of 1.5 × 1 cm and
1.5 × 0.5 cm were located respectively in the right and left
submandibular region of the neck with normal overlying skin. He had a 3+
pitting edema in both lower extremities. The remainder of the
examination was unremarkable.
A chest radiograph showed no abnormal opacities, cavitations, or
perihilar lymph nodes.
Laboratory findings of the patient are summarized in Table 1.
24-hour urine volume, proteinuria, and creatinine were reported 1100 ml,
3100 mg/day, and 1.4 mg/dL, respectively.
Urinalysis showed a specific weight of 1.025, red blood cells (15
cells/μl), and 2-4 granular casts in the urine sediment.
The results of rheumatologic and communicable disease screening tests
were negative and in the normal range. Ultrasound examination of the
thyroid gland showed thyroid lobes and isthmus with normal size and
parenchymal echogenicity with no sign of solid or cystic lesion.
Ultrasonography of lymph nodes showed evidence of multiple
lymphadenopathies on both sides of the neck, the largest of them
measuring about 15 ×7 mm in the right submandibular region and 12 × 5 mm
in the left carotid sheath.
In the setting of high serum levels of lactate dehydrogenase (LDH) and
erythrocyte sedimentation rate (ESR), metastases of unknown origin and
lymphoma were the highest diagnostic priorities, so the excisional
biopsy of the largest mass (15 ×7 mm) was performed.
Microscopic examination of stained sections (Figure 1) showed lymph
nodes with reactive follicles and prominent germinal centers.
Eosinophilia and capillary hyperplasia were also evident. These
histological characteristics were consistent with KD.
IgE serum levels were checked to make a definite diagnosis, which was
reported 3425 g/L↑ (normal range, 0-200 g/L) with IgG, IgM, and IgA
within normal ranges.
The treatment was started with oral prednisolone (15 mg/day) and
mycophenolic acid (500 mg, bid), which resulted in a noticeable clinical
improvement in the edemas and attenuation of proteinuria. The patient
had a remarkable recovery and was discharged on day 10th of admission.
In a one-year follow-up, he was asymptomatic with lowered eosinophil
count and no evidence of renal involvement relapse.