Pediatric Adrenal Hydatid Cyst: A Case Report and Literature Review

Abstract Introduction: Echinococcosis is a zoonotic disease that can affect various organs and tissues in the human body. However, primary adrenal hydatid cyst (AHC) is rare and may be overlooked, making its early detection crucial. This report presents a case of an incidentally diagnosed primary AHC. Methods: A 5-year-old female with an unremarkable medical history underwent abdominal ultrasonography for assessment of an inguinal hernia, and a right adrenal lesion was incidentally discovered. Intraoperatively, the lesion was suspected to be AHC, which was later confirmed by histopathology. Results: The 10 cases of AHC that were reviewed had a mean age of 46.2 ± 12.2 years; six patients were male. Three cases had a history of contact with animals. No laterality differences were observed, and the mean cyst size was 7.45 ± 2.7 cm. Flank pain was the most common symptom (3 of 10), and surgery was performed for all the cases, accompanied by antiparasitic drugs in five cases. No cases of recurrence were reported. Conclusion: Primary AHC can be easily overlooked or misdiagnosed as an adrenal mass, often being identified incidentally during investigations for unrelated health concerns. Surgical excision of the cyst without rupture may yield favorable results. Introduction Echinococcosis is a widely recognized zoonotic disease caused by the larval form of the tapeworm Echinococcus granulosus [1]. Although the disease can occur globally, it is considered endemic in several regions, including the Middle East, the Mediterranean basin, parts of South America, South Africa, and Australia [1]. Humans serve as accidental intermediate hosts for the parasite, acquiring the infection through direct contact with definitive hosts (such as dogs) or via ingestion of food or water contaminated with feces that contain parasitic eggs, often originating from livestock environments involving sheep, goats, or cattle [2]. Major risk factors include close contact with dogs, involvement in livestock activities, and living in endemic areas [2]. The prevalence of hydatid cysts in children differs by region, with a reported incidence of 2-6 cases per 100,000 children affecting individuals as young as six months old. Human infections typically occur incidentally through the ingestion of parasite eggs in contaminated food or water or by direct contact with infected hosts [3,4]. Hydatid cysts (HCs) are typically found in the liver and lungs, while the adrenal gland is a rare and unusual site of involvement [5]. This report presents a case of a primary adrenal HC (AHC) that was incidentally diagnosed in a child. The references cited in this report have been reviewed to ensure the exclusion of any non-peer-reviewed data, and the study has been structured following the CaReL guidelines [6,7]. Case presentation Patient information and clinical findings A 5-year-old girl presented with a two-month history of reducible inguinal swelling on the left side. She had undergone a left inguinal herniotomy nine months earlier. The swelling, consistent with a recurrent inguinal hernia, increased in size during episodes of coughing or crying. Otherwise, her past medical history was unremarkable. She belonged to a socioeconomically poor family with limited education and resided in an urban area. Notably, her grandfather, who lived in a rural area and had direct contact with animals, had a history of HC. Diagnostic approach Ultrasonography was performed to rule out a right-sided inguinal hernia. Incidentally, it revealed a well-defined 30 × 20 mm lesion with a central cystic area between the right kidney's upper pole and the liver's right lobe, suggesting an adrenal lesion. Five days later, a follow-up ultrasound conducted by another radiologist identified a similar well-defined lesion measuring 31 × 19 mm. Subsequently, the patient was referred to a pediatric hematologist for further evaluation. Laboratory investigations revealed a normal complete blood count. Urinalysis indicated the presence of mucus, while aspartate aminotransferase (38 IU/L, Normal range: 15–40 IU/L) was borderline elevated, lactate dehydrogenase (370 IU/L, Normal range: 100–250 IU/L ), and erythrocyte sedimentation rate (28 mm/hr, Normal range: 0–10 mm/hr) were elevated. Computed tomography (CT) of the chest and abdomen demonstrated a well-defined, irregular, heterogeneous mass in contact with the right adrenal gland, with evidence of invasion into segment VII of the liver and involvement of the posterior right hemidiaphragm (Figure 1). Therapeutic intervention Following a multidisciplinary discussion, the patient underwent surgery under general anesthesia. The procedure involved complete resection of the mass through a 10cm right subcostal incision, along with the excision of several ipsilateral lymph nodes for histopathological analysis (Figure 2). Subsequently, a left-sided herniotomy for the recurrent hernia was performed. Albendazole was administered postoperatively. Follow-up On the eighth postoperative day, the surgical wound was clean and dry. Histopathological examination revealed an infected wall of HC, accompanied by a granulomatous reaction, with adherent and compressed adrenal and liver tissue (Figure 3). Additionally, the ipsilateral lymph nodes exhibited reactive follicular hyperplasia. The patient's recovery was uneventful, and she remains under ongoing follow-up care. Discussion Four distinct types of Echinococcus have been recognized as responsible for hydatid disease in humans, with E. granulosus being the most commonly encountered type (95%) [8]. The disease can affect all organs and tissues in the human body [9]. The mechanism behind adrenal involvement remains unclear. The most plausible theory suggests that once the larvae exit the digestive system, they pass through the hepatic filter to reach the lungs. If they evade destruction by the immune system or are not trapped in the filtration system, they can spread out to the unusual sites of the body, such as the spleen, kidneys, brain, bones, heart, muscle tissue, pancreas, retroperitoneum, thyroid, and adrenal glands via the arterial circulation [5]. Larvae can also disseminate through systemic circulation via lymphatic vessels or direct adjacent contact [5]. AHC is a rare entity, accounting for only 0.073% of all hydatid cyst cases [9]. While individuals of all ages can be affected, this condition is more frequently seen in those aged 50 to 60, with a slightly higher prevalence in women [10]. However, the 10 reviewed cases had a mean age of 46.2 ± 12.2 years; six patients were male. The youngest case was an 18-year-old male, and the oldest was a 64-year-old male [5, 8-16]. The present case was only a 5-year-old female, which seems to be an infrequent age for this disease. Children can contract the infection through several pathways, such as direct contact with infected animals or consuming contaminated food or water. Furthermore, the higher prevalence of HCs in endemic areas accounts for the increased incidence in younger age groups. The disease typically presents as unilateral in 92% of cases and does not exhibit a preference for either side [11]. This is supported by the fact that the disease was unilateral in all 10 cases reviewed in this report, with no differences in laterality observed (Table 1) [5, 8-16]. HCs are typically asymptomatic and often found incidentally during imaging studies for other reasons. They seldom lead to complications and usually become symptomatic primarily due to pressure-related effects [8]. Table 1. Summary of 10 reported cases of adrenal hydatid cysts Author /year [reference] Age (Y) Sex Country Contact with animals Tumor size (cm) Side Symptoms Medical history Therapeutic approach Recurrence Follow-up (M) Zouari et al./ 2020 [5] 55 N/A Tunisia N/A 12 Left Left hypochondrium pain None Surgery N/A N/A Tajmalzai et al./ 2025 [8] 18 M Afghanistan Yes 5.2 Right Right side flank pain None Albendazole & Surgery No N/A Agarwal et al./2024 [9] 38 M India N/A 6.8 Right Vague abdominal pain None Surgery & Albendazole No 12 Staouni et al./ 2022 [10] 46 F Morocco N/A 6 Left Left hypochondrial pain None Surgery No 12 Salih et al./ 2018 [11] 48 F United Arab Emirates Yes 7.2 Left Large palpable mass, moderate left loin pain None Laparoscopic surgery N/A N/A Tazi et al./ 2012 [12] 64 M Morocco No 11.3 Left Left flank pain nausea & vomiting Arterial hypertension Surgery No 24 Elzein et al./ 2016 [13] 44 M Saudi Arabia Yes 7.1 Right Flank pain N/A Surgery & Albendazole N/A N/A Abdulmajed et al./ 2010[14] 48 F Turkey No 5.2 Right Vague right loin pain Systolic hypertension Surgery & Albendazole N/A N/A Bouchaala et al./ 2021[15] 46 M Tunisia No 9.7 Right Non-specific abdominal pain Abdominal pain & weight loss Surgery & Albendazole No N/A Nardi et al./ 2015 [16] 55 M Argentina N/A 4 Left Back pain None Laparoscopic surgery N/A N/A M: male, F: female, N/A: non-applicable,Y: Years, M: months The most common symptoms are pain (hypochondriac or flank pain), nausea and vomiting, and palpable mass, usually due to inflammation of adjacent tissues caused by the cyst. Systemic symptoms may also occur, such as hypertension resulting from renal artery occlusion or symptoms that mimic pheochromocytoma due to compression of the adrenal medulla by cysts [9]. The most severe complication of HCs is cyst rupture, leading to anaphylaxis and bleeding [5,10]. Flank pain was the most common presenting symptom among the reviewed cases (3 of 10), with no systemic or severe complications reported [5,8-16]. Consistent with the literature, the present case was asympto