Metastatic Sinonasal and Right Orbital Adenocarcinoma Secondary to Right Breast Lesion

Matthew P. Nemoy; Macksood Aftab, DO, MHA, ALM, CAQ

Disclosures

Appl Radiol. 2019;48(2):32-33. 

In This Article

Discussion

The radiographic appearance of this case suggests one of two diagnoses: acute invasive fungal sinusitis with skull base and orbital erosion and dural involvement, or dural metastasis with sinus invasion. Both can present with hyperdense soft tissue in the sinuses with corresponding decreased T2 signal and osseous erosive change. The exact diagnosis requires correlation with clinical presentation and laboratory values specifically correlation with neutrophil count.

Metastatic disease to the sinuses and orbit is rare, making this case unique both from an imaging study and differential diagnostic standpoint. The patient did have a suspicious, untreated right breast lesion upon presentation and surgical pathology indicated it was consistent with carcinoma with possible metastatic disease. These findings raised the suspicion that the current, presenting chief complaints of four to five weeks of blurry vision, facial pressure, and fatigue could be related to the patient's breast lesion. This is where imaging can be helpful.

Computed tomography a common diagnostic modality for evaluating invasive sinusitis and metastatic disease, as it allows for well-defined visualization of the osseous anatomy. High-resolution facial bone CT is best at demonstrating bony erosion and expansion of the infection. MRI imaging is required to further refine the differential, as was done with this patient. Hyperdense soft tissue opacification as well as decreased T2 weighted signal observed on the imaging studies is characteristic of fungal sinusitis. Given the extensive nature of this patient's sinonasal symptoms, combined with the osseous erosions seen on CT and the decreased signal noted on T2-weighted MRI, consultation between neuroradiology and otolaryngology resulted in the patient's transfer to a tertiary care facility for urgent surgical evaluation and debridement. Surgical pathology at the tertiary care center revealed metastatic sinonasal and right orbital adenocarcinoma secondary to the patient's right breast lesion. From a radiological perspective, this diagnosis poses an interesting challenge as findings represented metastatic disease mimicking what appeared to be acute invasive fungal sinusitis.

Figure 1.

CT and MRI imaging of a patient with acute incasive fingal sinisitis. CT imaging demonstrates (A) hyperdense soft tissue obstructing the right sphenoid sinus and (B) osseous erosion of the right ethmoidal air cells. T2-weighted MRI demonstrates (C) soft tissue extending into the right orbital apex of the optic nerve and (D) osseous erosion of the cribiform plate.

In addition to metastatic disease, acute invasive fungal sinusitis is an important clinical problem that should be considered when constructing a differential diagnosis for the immunocompromised patient, such as a patient with cancer. Acute invasive sinusitis typically develops over a few weeks and can demonstrate hyphal invasion of blood vessels.[1] Common causes of immunosuppression that can result in fungal sinusitis include: malignancies, neutropenia following chemotherapy, diabetes mellitus, and glucocorticoid use.[2] Acute, invasive infections infections are usually due to Aspergillus species, Fusarium species, and Mucorales.[3] Fungal sinusitis typically involves multiple sinuses with the most common being the ethmoid and maxillary sinuses.[3] If suspecting fungal sinusitis, consult an otolaryngologist for nasal endoscopic evaluation. Typically, patients with fungal sinusitis will demonstrate necrotic lesions on their nasal septum during physical exam. Our patient failed to demonstrate these physical exam findings, so despite imaging studies suggestive of a fungal pathogen, invasive fungal sinusitis became a less likely diagnosis.

Finally, another useful tool to consider when using imaging studies to determine whether a patient with an underlying malignancy has fungal sinusitis versus metastatic disease is the patient's absolute neutrophil count.[4] Patients with an absolute neutrophil count <500/microliter are more likely to have a diagnosis of acute invasive fungal sinusitis.[5] The patient's absolute neutrophil count was documented well above 500, making fungal sinusitis less likely.

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