Pediatric Eosinophilic Granuloma Associated With Delayed Epidural Hematoma Following on Seizure: A Case Report

Eosinophilic granuloma (EG), a subtype of Langerhans cell histiocytosis (LCH), the monostotic form characterized by a solitary bone lesion, is a rare neoplasm that is mainly observed in the pediatric population [1, 2]. The clinical manifestations of EG are usually destructive bony lesions. The skull is the most commonly involved site, followed by the femur, mandible, and ribs [3]. Most children with skull EG present with an asymptomatic enlarging mass [3].

Around 33%–50% of documented LCH cases that involve epidural hematoma (EDH) are linked to a preceding head trauma [4, 5]. Nevertheless, the occurrence of skull EG with hematoma is exceedingly uncommon [6]. Here, we report a rare case of a 32-month-old boy with a left suboccipital mass complicated by EDH. Upon conducting a thorough literature review, only 14 cases of EG associated with EDH were recognized (Table 1) [1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]. In the present case, the patient did not initially exhibit any clinical symptoms. However, delayed EDH developed following a seizure.

Table 1
Case reports of Langerhans cell histiocytosis associated with epidural hematoma

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A 32-month-old boy arrived at the emergency room after falling from a height of around 70 cm. Despite the absence of any notable neurological abnormalities, a palpable mass was noted in the suboccipital region. A CT scan revealed an osteolytic skull mass measuring 2.5×1.5 cm in the suboccipital region without evidence of hemorrhage (Fig. 1).

Fig. 1
Preoperative radiologic findings. A: CT showing an osteolytic mass. B: T1-enhanced signal showing a markedly enlarged cystic lesion on the follow-up MRI scan taken 3 weeks after the fall.

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During the wait for a scheduled surgery date, the patient encountered a brief period of decreased alertness, resembling a dialeptic seizure, and sought medical attention. A non-enhancing mass was noted on the left occipital skull on the 3 weeks post-fall follow-up MRI and there was subsequently enlarged extra-dural cystic lesion measuring 8×4 cm. The electroencephalography indicated a normal stage II–III sleep pattern.

We performed surgery to open the skull and remove the tumor, and the tumor, which contained a gel-like blood clot, was separated along with the tough outermost layer of the brain. The bony rim was uneven. The cystic lesion released a dark coke-colored fluid, which was identified as a blood clot. Pathological analysis confirmed the diagnosis of EG with areas of positive margins (Fig. 2).

Fig. 2
Gross image and histopathological analysis. A: The tumor is a tender osteolytic lesion with a crimson gelatinous hematoma appearance upon macroscopic inspection. B: During the pathological analysis, CD1a labeling shows affirmation and S-100 shows faint positivity. Affirmative edges are detected on the cryogenic biopsy.

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There was an increase of uptake in left distal radius and lumbar lesion on radioisotope whole body scan. A 6-week course of chemotherapy was administered according to the LCH III protocol (version 2.0) of the Histiocyte Society [16]. No evidence of recurrence was observed during the 1-year follow-up period.

LCH is a rare disorder characterized by the proliferation of myeloid progenitors with altered differentiation and phenotypic features similar to those of epidermal dendritic cells [6]. The reported incidence of LCH is 0.2–2.0 cases per 100,000 children under the age of 15 [17]. Radiologic investigations, especially CT scans, are crucial for diagnosing EGs, with the characteristic radiologic findings being non-sclerotic, sharply defined, lytic lesions in the skull [3, 11]. Histopathological analysis is typically used to confirm EG diagnosis [2].

Solitary EG lesions, especially on the skull, are the most common local form of LCH. EG commonly presents as an enlarged skull mass, possibly preceded by head trauma. In a study by Rawlings and Wilkins [18], 38% of patients presented with preceding trauma; however, the relationship between head trauma and skull mass development is unclear. However, EG presenting with hematoma is extremely rare, and the first case was reported by Manaka et al. [7] in 1977. Currently, only 14 cases, prior to the present case, have been reported.

Several mechanisms have been proposed for hematoma formation in EGs. These include rupture of the tumor cyst [8], communication with an epidural vein [3], invasion of the venous sinus [1], stripping of the dura due to rapid tumor growth, erosion of dural vessels, bleeding of the dural neovascularization caused by EG [10], and extension of intra-tumoral bleeding into the extradural space [12].

Our patient also had a preceding head trauma; however, the dural margin was positive, highlighting the possible mechanisms of dural stripping and dural vessel erosion due to rapid tumor growth. Although EG is considered a benign lesion, the overall outcome is not fully predictable, as both spontaneous regression and recurrence after surgical excision have been reported [1].

There have been several reports of local and distant recurrences during long-term follow-up; therefore, we decided to proceed with chemotherapy according to the LCH-III protocol recommended by the Histiocyte Society [16]. The patient was followed up for approximately 1 year after completing the chemotherapy regimen, without any signs of recurrence.

This case highlights the importance of considering EG in the differential diagnosis of a growing skull mass, even if it is accompanied by EDH. Early diagnosis and treatment can prevent serious complications and improve patient outcomes.