The available literature on skull metastasis of lung cancer was retrieved from PubMed. A total of eight reports were extracted from the database, and the initial clinical symptoms, position of metastasis, histology, therapy, and outcome are summarized in Table 1.
Table 1
Characteristics of cases of lung cancer with skull metastasis
author,
|
age/sex
|
initial clinical symptom
|
position of metastasis
|
cranial nerves implicated
|
histology
|
therapy
|
outcome
|
Mengoli MC, et al
|
55y/F
|
skull mass
|
Frontal bone
Parietal bone
|
-
|
adenocarcinoma
|
erlotinib
|
8 months
Stable
|
Zelenak M,et al
|
59y/F
|
acute cavernous sinus syndrome
|
sphenoid bone
|
II, III, IV, V, VI, VIII
|
non-small cell lung cancer
|
high-dose steroids + radiotherapy
|
2 weeks
Progression
|
Djeric D, et al
|
73y/F
|
facial palsy
|
temporal bone
|
VII
|
adenocarcinoma
|
-
|
died suddenly
|
Bakhos D, et al
|
76y/M
|
hearing loss
|
temporal bone
|
VIII
|
adenocarcinoma
|
carboplatin + taxotere + radiotherapy
|
5 months
died
|
74y/M
|
hearing loss
|
temporal bone
|
VIII
|
squamous cell carcinoma
|
carboplatin + taxotere + radiotherapy
|
3.5 months
died
|
Moriyama Y, et al
|
61y/F
|
Garcin Syndrome
|
posterior cranial fossa
|
IX, X,XI, XII
|
small cell lung cancer,
|
carboplatin + etoposide
|
24 months
stable
|
Fukai S, et al
|
76y/F
|
Garcin Syndrome
|
sphenoid bone
|
IV, V, VI
|
non-small cell lung cancer
|
Surgery + Radiotherapy + zoledronic acid
|
5 months
died
|
Moeller JJ,et al
|
58y/F
|
dysarthria and tongue weakness
|
occipital condyle
|
XII
|
small cell lung cancer,
|
radiotherapy
|
5 months
died
|
Takeuchi S, et al
|
64y/M
|
dysarthria and headache
|
occipital condyle
|
XII
|
adenocarcinoma
|
radiotherapy + chemotherapy
|
9 months
died
|
The clinical manifestations of tumor metastases differ depending on their location. Localized intraosseous tumors often appear as progressively growing skull masses. These can sometimes be very large but do not invade the dura mater and brain, in which case the patient may have no neurological damage, except for changes in appearance. In the current case, however, the tumor showed diffuse invasive growth, and the patient had “mass effect” and neurological dysfunction. If the tumor involves the skull base, most cranial nerves can be involved, resulting in paralysis[4–10]. Tumors of the middle and posterior fossa involve more nerves, and patients can show different syndromes, such as acute cavernous sinus syndrome, Garxin syndrome, and occipital condylar syndrome. Notably, not all patients have a history of lung cancer followed by metastatic symptoms; the metastatic symptoms may sometimes occur first, while the primary lung cancer is only detected after further examination[9, 11].
Most patients with skull metastasis of lung cancer have a very poor prognosis, especially when the tumor invades the skull base and cannot be removed by surgery. Even different radiotherapy and chemotherapy schemes may not result in an ideal response, and patients often die within months of their diagnosis, or are at risk of sudden death[5]. The current patient initially refused surgical treatment because of the surgical risk. However, subsequent extensive infiltration made surgery more difficult, with the huge tumor penetrating the subcutaneous tissue, muscle, skull, and dura mater, and being deeply rooted in the brain. Full resection should therefore be performed as early as possible in patients with craniofacial metastases, followed by radiochemotherapy. However, progress in targeted therapy means that increasing numbers of drugs are becoming available to improve patient survival.
Serious complications may occur during treatment. A previous report[12] found that invasive skull metastases caused severe intracranial hemorrhage 3 weeks after radiotherapy and chemotherapy, eventually leading to death. Although the authors could not conclusively determine if the tumor had transferred from the skull to the brain, because of technical limitations, they concluded that this was likely. This scenario was further supported by our current case. Initial imaging showed that the tumor was limited to the skull and epidural space, but subsequently grew and infiltrated into the surrounding soft tissues, dura mater, and brain parenchyma. This case provides good imaging evidence for the infiltrating growth process of skull metastases in lung cancer. Although our patient did not develop a fatal intracerebral hemorrhage, postoperative epidural effusion and infection posed serious life-threatening complications. During the operation, we removed the tumor infiltrating the subcutaneous tissue, muscle, skull, and dura mater and repaired it with an artificial dura. Cranioplasty was not carried out because of the need for radiotherapy. There is a potential space between the artificial dura and subcutaneous tissue, which provides the anatomical basis of epidural effusion. The current patient developed a scalp infection with an unknown cause 1 month after surgery. Before the infection, the patient had multiple subcutaneous effusions to relieve the tension of the epidural effusion, which might have caused the infection. Attention should thus be paid to the potential complications of epidural effusion.