Growing skull fractures: A case of post-traumatic leptomeningeal cyst in an adult and a review of literature

Growing skull fractures (GSFs) are a rare condition characterized by the formation of a leptomeningeal cyst resulting from dural tears following a skull fracture. GSFs are often underdiagnosed in adults, making history taking, neurological examination, and imaging crucial. Symptomatic cases may need surgery, while asymptomatic ones can be managed conservatively. Greater awareness is essential for early diagnosis and optimal management. Growing skull fractures (GSFs) represent a rare subset of skull fractures (0.05%–1.6%), often underdiagnosed or misinterpreted due to their atypical presentation.¹ They result from major head trauma, leading to dural tears and brain tissue herniation into the fracture site, ultimately causing encephalomalacia and cyst formation.²

A 22-year-old male presented to the emergency department following a 1st-time seizure characterized by tonic–clonic movements, up-rolling of the eyes and frothy secretions from the mouth. He was in a post-ictal state upon arrival but regained consciousness without remarkable findings on physical examination. The patient had no relevant medical history but recalled a childhood fall. A CT scan revealed a leptomeningeal cyst, attributed to the earlier head injury (Fig. 1).

Close

FIG 1.

Brain CT images (axial view; arrow shows leptomeningeal cyst formation)

Export to PPT

The adult presentation of GSF is rare. Britz et al. reviewed 5 cases of adult GSF in 1998, with ages ranging from 28 to 53 years, all presenting with a firm non-tender mass on scalp examination (3 parietal, 1 frontoparietal and 1 middle cranial).³ Yan et al. reviewed 70 reported cases of GSF, with 21.4% (15 cases) being over 18 years. The most common physical sign was a progressively enlarging swelling of the scalp, accounting for over one-third of all cases (n=24, 34.3%), followed by a non-pulsatile mass (n=12, 17.1%) and a palpable cranial defect (n=9, 12.9%).⁴ GSFs pose diagnostic challenges, particularly in adults. Imaging modalities such as CT and MRI play a vital role in confirming the diagnosis and evaluating associated complications. The symptomatology of GSF on presentation can vary. The current literature indicates that the typical clinical presentation of leptomeningeal cysts in children is a non-tender, pulsatile scalp mass or follow-up X-rays showing progressive enlargement of a skull fracture following head trauma.³ In a large series of 132 patients with GSF identified by Pezzotta et al., 42% of patients presented with seizures, 43% with neurological deficits and 38% with loss of consciousness.⁵

We did a comprehensive literature review of GSF in adults in PubMed. The inclusion criteria were all reported cases of individuals aged 18 years or older with a confirmed diagnosis of GSF on CT or MRI, and studies published in English. We excluded all those under 18 years of age, duplicate reports and cases with unconfirmed diagnoses. A total of 22 cases were identified from 1946 to 2021. Among the 22 cases reviewed (14 males and 8 females; mean age 40.5 years), parietal fractures appear to be the most common, accounting for 8 of the 22 cases reviewed (36.4%). Common presentations include headache (36.4%), seizures (18.2%) and focal neurological symptoms such as proptosis and visual disturbances (13.6%), among other complaints (fainting, nasal discharge, dizziness, etc.). A thorough history, especially regarding trauma and mechanism, a comprehensive neurological examination and appropriate imaging, is crucial for diagnosing GSFs before symptoms appear. While an MRI can determine the full extent of damage, a CT scan is typically sufficient.^6,7 The management of GSF has advanced over the past few decades. For asymptomatic or minimally symptomatic cases, observation and symptom management may suffice.⁸ However, symptomatic patients, particularly those with progressive neurological deficits or seizures, often require surgery. Surgical options range from cyst excision and dural repair to cranioplasty and cranial vault reconstruction, with techniques such as pericranial dural inlay grafts and cranial bone grafts ensuring good functional and aesthetic outcomes, especially in children.^9,10 Further research is needed to uncover the exact pathogenesis and risk factors associated with these fractures. Increased awareness and understanding of GSF will help facilitate early diagnosis and appropriate management of affected individuals.