We describe a case of intracranial mucormycosis in an immunocompetent child with perfusion features mimicking a brain tumor. Saksenaea species has previously been reported in immunocompetent patients. The source of the infection in our patient was unknown. On brain MRI, the unusual curvilinear and nodular enhancement pattern may reflect the angioinvasive nature of the organism, not previously reported. The finding of increased CBV is typically associated with neoplasms, with CNS infections typically demonstrating decreased CBV. This case demonstrates that fungal infection may present with increased CBV.
4-year-old healthy male presented to the emergency room
with intractable vomiting, worsening right frontal headaches for
one month, and drowsiness for one day. Head CT demonstrated
an ill-defined hyperdense right frontal lobe lesion (Figure 1). MRI
showed an irregularly enhancing right frontal lobe lesion which
extended to the corpus callosum. Subtle associated diffusion
restriction was noted with increased cerebral blood volume
(Figure 2). A high-grade, hypercellular tumor was suspected,
although the enhancement pattern was unusual. A generous brain
biopsy was performed with intraoperative pathology revealing
granulomatous fungal encephalitis and the lesion was grossly illdefined.
Tissue culture confirmed growth of Saksenaea species.
Extended work up ruled out diabetes, immunodeficiency,
and disseminated systemic fungal infection, including blood
work for congenital or acquired immunodeficiencies (serum
immunoglobulins for humoral deficiency, lymphocyte subsets
for cellular deficiency, and CH50 for complement deficiency,
oxidative burst for chronic granulomatous disease, Quantiferon
Gold for TB, and HIV), a chest CT for fungal respiratory infection,
an echocardiogram, a complete ophthalmic exam, and gastric
endoscopy. He completed a course of daily IV liposomal
amphotericin B 10mg/kg for 14 weeks and is currently on the
same daily total dose but three times weekly. The plan is to
continue antifungal medications for a minimum of 12 months.
He has also been on posaconazole IV (dose adjusted per serum
trough) and terbinafine 6.5mg/kg/day enterally. He also received
hyperbaric therapy for 14 treatments (Figure 3).
He has spent the past 6 months in the hospital. Despite poor
prognosis, parents have chosen for him to receive full treatment.
He is now status post decompressive hemicraniectomy secondary
to refractory intracranial hypertension, in a minimally conscious
state, dependent on gastrostomy feeding and a tracheostomy
tube without mechanical ventilation. He has severe spasticity
and paroxysmal sympathetic hyperactivity, which are treated
with medications (clonidine, diazepam, baclofen and dantrolene),
physical, and occupational therapies.
Rhinocerebral mucormycosis is a rare opportunistic infection
of the sinuses, nasal passages, oral cavity, and brain caused
by saprophytic fungi. Rhino-orbital-cerebral mucormycosis
(ROCM) is a life-threatening rare, opportunistic, and severe
angioinvasive infection, which is typically seen in patients with
severe immunodeficiencies such as hematological malignancies
undergoing chemotherapy, or in diabetic patients [1,2]. However,
Saksenaea species in the order Mucorales has previously been
reported in immunocompetent patients .
Based on anatomic localization, mucormycosis can be
classified as 1 of 6 forms:
e) Disseminated, and
f) Uncommon presentations .
Manifestations of mucormycosis depend on the location of
involvement. Central nervous system (CNS) disease manifests as
headache, decreasing level of consciousness, and focal neurologic
symptoms/signs including cranial nerve deficits. Patients with CNS
involvement may have a history of open head trauma, intravenous
drug use, or malignancy. Here we discuss an unusual case of
intracranial mucormycosis, presenting in an immunocompetent
patient as an intracranial mass lesion. The source of the infection
in our patient is unknown.
Brain lesions are typically T1 isointense with variable T2
intensity on MRI . MRI signal intensity of mucormycosis
lesions tends to be isointense or hypointense in all sequences.
After the administration of gadolinium, the lesions typically have
variable enhancement patterns (ranging from homogeneous
to heterogeneous or no enhancement) . Diffusion weighted
imaging typically shows markedly reduced diffusion . The
unusual curvilinear and nodular enhancement pattern in our
case may reflect the angioinvasive nature of the organism, not
previously reported. The finding of increased cerebral blood
volume (CBV) is typically associated with neoplasms, with CNS
infections typically demonstrating decreased CBV . This case
demonstrates that fungal infection may present with increased
Current guidelines on treatment of ROCM include prompt
initiation of liposomal amphotericin B therapy and complete
surgical resection, when possible . Adjunctive therapies
such as hyperbaric oxygen, colony-stimulating factors, and iron
chelators are all controversial. Mycormycosis is one of the rapidly
progressing and lethal form of fungal infection. Risk factors
include diabetes and neutropenia . The underlying conditions
can influence clinical presentation and often delay diagnosis,
with resultant poor outcomes . Patients with rhinoceerbral
mycormycosis spreading outside the sinonasal cavity have a poor
prognosis despite aggressive surgical debridement and medical
management  (Table 1).
Tumor: A tumor is suspected when a focal density or signal
alteration is seen displacing or infiltrating adjacent structures
with or without a matching contrast enhancement and possibly
surrounded by vasogenic edema. High grade tumors typically
show increased CBV.
Abscess: the classic tumor-like lesion is an intracranial abscess
. Most intracranial abscesses are bacterial (staphylococcus, streptococcus, and pneumococcus). Intracranial abscesses may
present with imaging features that are identical to high-grade
neoplasms. Abscesses are round, mass lesions with various
degrees of adjacent vasogenic white matter edema and a strong
peripheral contrast enhancement. The ring of enhancement is
usually closed and may appear thicker towards the direction of the
cortex. The pus within the abscess typically showed a restricted
diffusion on diffusion-weighted imaging (DWI), whereas necrosis
in the center of malignant tumors typically shows an increased
Subacute ischemia: These lesions may have a significant
mass effect with irregular contrast enhancement. The clinical
history with acute onset of symptoms and a matching clinical
history can assist with differential. Most lesions are located within
a vascular territory with simultaneous involvement of cortex and
adjacent white matter. Anatomic MRI shows restricted diffusion
on DWI and hypoperfusion on perfusion-weighted imaging (PWI).
Demyelination: Various demyelinating diseases, including
tumerfactive multiple sclerosis (MS), acute disseminated encephalomyelitis,
and progressive multifocal leukoencephalopathy may
present tumor-like. Typically, MS plaques show an incomplete
ring of contrast enhancement towards the cortex. Advanced imaging
can be helpful for diagnosis, including DWI, MRS and PWI.
Tumefactive plaque typically shows marginal diffusion restriction
and an aggressive spectroscopic profile with increased choline,
decreased NAA and presence of lactate. CBV would typically be
decreased. A rapid response of the lesion to corticosteroid treatment
is suggestive of demyelinating disease. Tumors and abscesses
do not respond quickly (Table 2).