August 2023 Medical Image of the Month: Cannonball Metastases from Metastatic Melanoma

Figure 1. Upright PA chest radiograph (A) demonstrates innumerable rounded nodules with a slight lower lung predilection. Coronal reconstruction from a subsequent chest CT with contrast (B) confirms innumerable round, solid and non-calcified pulmonary nodules most consistent with a “cannonball” pattern of pulmonary metastatic disease.

Figure 2. Axial susceptibility-weighted (A) and pre-contrast T1-weighted (B) images from a brain MRI centered on one (of many) intracranial lesions. This lesion in the posterior right cerebral hemisphere demonstrates a large amount of surrounding susceptibility artifact (A) consistent with blood product, indicating a hemorrhagic metastasis, common in metastatic melanoma which can be very vascular in nature.  There is elevated T1 signal surrounding the lesion (B), also consistent with hemorrhage. There is T1 signal in the center of the lesion as well (arrow), which could represent hemorrhage but could also represent melanin, which is T1 bright and can suggest the primary tumor histology (melanoma).

A 48-year-old man with a significant smoking history presented with progressive dyspnea, a mildly productive cough with brown-tinged sputum, headache, weight loss, and progressive back pain over a period of 8 weeks. The patient had no known history of lung conditions. As part of their initial evaluation, the patient received a frontal CXR and was found to have innumerable rounded pulmonary nodules throughout the lungs, which were consistent with a “cannonball” pattern of pulmonary metastatic disease (Figure 1A). A subsequent CT confirmed innumerable pulmonary metastases (Figure 1B). An MRI of the brain and spine revealed hemorrhagic brain metastases (Figure 2), spinal metastases, and bone metastases. A biopsy of a lesion in the left iliac bone confirmed the diagnosis of metastatic melanoma.

This case highlights the so-called “cannonball” pattern of pulmonary metastatic disease with innumerable round nodules throughout the lungs with a slight lower lung predilection, consistent with a hematogenous spread of disease to the lungs. Classically, this pattern consists of numerous well-circumscribed relatively large lesions in the lungs with a pattern resembling multiple small "cannonballs". The distribution of nodules is random, and the factors that distinguish a cannonball pattern from a miliary pattern of pulmonary metastatic disease are that cannonball metastases are larger and less numerous compared to a miliary pattern of pulmonary metastatic disease (1,2). Although cannonball pattern of pulmonary metastatic disease is classically described in the setting of metastatic renal cell carcinoma, prostate cancer, choriocarcinoma, and sarcoma, it has been reported for a variety of other primary cancers, including melanoma. Similar cases of late-stage metastatic melanoma presenting as widely metastatic disease of unknown origin has also been reported (3).

Melanoma spreads to the lungs through hematogenous dissemination, resulting in the cannonball (or miliary) lesions observed on imaging. Specifically, when these lesions are small and distributed throughout the lung, they commonly indicate metastatic melanoma. While this classical presentation can be pathognomonic, it is important to consider other potential diagnoses, including malignancy, infectious diseases, and rheumatologic conditions. Malignant causes encompass metastatic colorectal cancer, breast cancer, renal cell carcinoma, choriocarcinoma, prostate carcinoma, and adrenal carcinoma. Additionally, non-cancerous causes include infectious etiologies such as septic emboli, coccidiomycosis, histoplasmosis, miliary tuberculosis, and nocardiosis. It is also important to note that rheumatologic conditions like granulomatosis with polyangiitis (Wegener's granulomatosis) can present with the cannonball sign; however, they typically involve both the upper and lower lungs. In this case, the lesions were determined to be due to metastatic melanoma, which had spread to the lungs via hematogenous dissemination.

For this patient, an oncologist was consulted, who recommended that the patient undergo treatment with ipilimumab and nivolumab. The response rate for this treatment regimen generally exceeds 50%, and more than 50% of individuals continue to survive after 5 years. Frequently, when extensive metastases are observed on imaging, healthcare providers often assume a limited life expectancy and tend to lean towards discussions of hospice care. However, it is important to keep in mind that even in cases of extensive metastatic disease, many cancers can be effectively treated with novel and highly effective immunologic anticancer medications.

Andrew Barsoum MD, Mueez Hussain MD, Ranjit Sivanandham MD, and Sina Bagheri MD.

Southwest Healthcare System

Murrieta, California 

References

1. Ammannagari N, Polu V. 'Cannon ball' pulmonary metastases. BMJ Case Rep. 2013 Jan 8;2013:bcr2012008158. [CrossRef][PubMed]
2. Andreu J, Mauleón S, Pallisa E, Majó J, Martinez-Rodriguez M, Cáceres J. Miliary lung disease revisited. Curr Probl Diagn Radiol. 2002 Sep-Oct;31(5):189-97. [PubMed]
3. Lowe A, Bray JJH. Late-stage melanoma presenting with cannonball metastases. BMJ Case Rep. 2020 Dec 12;13(12):e237969. [CrossRef][PubMed]

Cite as: Barsoum A, Hussain M, Sivanandham R, Bagheri S. August 2023 Medical Image of the Month: Cannonball Metastases from Metastatic Melanoma. Southwest J Pulm Crit Care Sleep. 2023;27(2):23-25. doi: https://doi.org/10.13175/swjpccs025-23 PDF

Medical Image of the Month: Severe Acute Respiratory Distress Syndrome and Embolic Strokes from Polymethylmethacrylate (PMMA) Embolization

Figure 1. The contrast-enhanced CT of the chest on the left (Panel A) was acquired at the time of admission. The contrast-enhanced CT of the chest on the right (Panel B) was obtained 3 days into the hospitalization. The initial study demonstrated ground glass opacities most pronounced in the upper lobes, left greater than right. The follow up CT demonstrated marked progression of her airspace disease bilaterally, consistent with the clinical picture of the adult respiratory distress syndrome (ARDS).

Figure 2. An axial susceptibility weighted image (SWI) of the brain demonstrates extensive foci of susceptibility artifact (black dots) most pronounced in the genu and splenium of the corpus callosum (blue arrows) and the bilateral internal capsules (red arrows) – most consistent with embolic phenomenon.

A 35-year-old lady with a history of depression and anxiety presented to the emergency room with worsening shortness of breath after receiving polymethylmethacrylate (PMMA) injections in her buttock for cosmetic purposes in Mexico. Immediately after the injection in the outpatient office, she became acutely short of breath, tachypneic, and tachycardic. She was brought to the emergency room where she was hypoxic with oxygen saturations in the low 80s on a non-rebreather, tachypneic with a respiratory rate in the 40s, and tachycardic with heart rates in 140s. She was emergently intubated. A CTA of the chest demonstrated bilateral ground glass opacities throughout, most pronounced in the upper lobes which progressed to significant bilateral airspace disease consistent with acute respiratory distress syndrome (Figure 1). Her neurological examination declined over the course of her hospitalization. An MRI of the brain with contrast demonstrated bilateral foci of susceptibility artifact throughout the entirety of the brain most consistent with an embolic phenomenon in the setting of a suspected right-to-left shunt (Figure 2). Her mental status did not improve during her hospital course, and her family was deciding on whether to pursue comfort measures.

Discussion: Embolic complications of PMMA have been documented in the literature in relation to interventional procedures of the spine where it is used as a cement (i.e. vertebroplasty/kyphoplasty) (1). In those instances, the emboli are radiopaque and can be identified on conventional imaging modalities such as chest radiography or CT imaging (2). In the case of our patient, we were not able to confirm the exact formulation of the PMMA, but we suspect that it was delivered in the form of a dermal filler which was likely in the form of particles/microspheres. Migration of the particles/microspheres in the form of vascular emboli can occur if injected into blood vessels during procedures (3).

Sooraj Kumar MBBS¹, Sharanyah Srinivasan MBBS¹, and Tammer El-Aini MD²

¹Banner University Medical Center – South Campus, Department of Internal Medicine

²Banner University Medical Center – Main Campus, Department of Pulmonary and Critical Care

References

1. Abdul-Jalil Y, Bartels J, Alberti O, Becker R. Delayed presentation of pulmonary polymethylmethacrylate emboli after percutaneous vertebroplasty. Spine (Phila Pa 1976). 2007 Sep 15;32(20):E589-93. [CrossRef] [PubMed]
2. Yeom JS, Kim WJ, Choy WS, Lee CK, Chang BS, Kang JW. Leakage of cement in percutaneous transpedicular vertebroplasty for painful osteoporotic compression fractures. J Bone Joint Surg Br. 2003 Jan;85(1):83-9. [CrossRef] [PubMed]
3. Lemperle G, Morhenn VB, Pestonjamasp V, Gallo RL. Migration studies and histology of injectable microspheres of different sizes in mice. Plast Reconstr Surg. 2004 Apr 15;113(5):1380-90. [CrossRef] [PubMed]

Cite as: Kumar S, Srinivasan S, El-Aini T. Medical image of the month: severe acute respiratory distress syndrome and embolic strokes from polymethylmethacrylate (PMMA) embolization. Southwest J Pulm Crit Care. 2021;22(4):86-7. doi: https://doi.org/10.13175/swjpcc008-21 PDF

Medical Image of the Week: Osmotic Demyelination

Figure 1. MRI of the brain with FLAIR hyperintensity within the pons (see arrow), no stroke or watershed infarction.

A 59 year-old woman with past medical history of diabetes mellitus type II and end stage renal disease (ESRD) on hemodialysis (HD) presented with a right ankle fracture. She missed two days of HD. Fifteen minutes into HD, she became confused, hypotensive, bradycardic and then unresponsive with generalized body stiffness for approximately one minute. She never lost her pulse. Her vital signs returned to normal spontaneously after this episode. Patient was intubated for airway protection because she was obtunded.

On examination, while she was off sedation, her eyes were open but she did not track or follow commands. She had a positive cough, gag and corneal reflex but oculocephalic reflex was absent with dysconjugate gaze. She had intact brainstem reflexes but absence of deep tendon reflexes. She had no movements of her upper extremities and did not withdraw to painful stimulus. MRI of the brain was obtained to rule out acute stroke and showed FLAIR hyperintensity within the pons, no stroke or watershed infarction (Figure 1). Laboratory showed no acute changes of sodium levels or glucose level.

After 7 days of hospitalization, she started to track with her eyes and follows commands. She was extubated on day 15 of hospital stay and was discharged to a rehabilitation center after a total of 25 days of hospital stay. She was awake, alert and oriented to time, place, and person and able to talk and move all four of her extremities.

The rapid deterioration of mental status with acute neurological changes in this case is typical for osmotic demyelination syndrome (ODS). The exact mechanism behind the demyelination remains not well understood but involves the inability of brain cells to respond to rapid changes in osmolality, and hence destruction of myelin and neurons. It can also occur in chronically debilitated patients without osmolality shift and ESRD may be a risk factor (1,2). MRI images may show large symmetrical lesions in the basis pontis, usually sparing the ventral pons, or there may be smaller “butterfly” or trident-shaped lesions in the base of the pons. The initial MRI images may reveal nothing abnormal especially in the acute phase (3).

ODS should be considered in ESRD patients who present with any neurological symptoms, unexplained behavioral disorder or neurologic signs related to the pons or brainstem region. ODS secondary to dialysis has favorable prognosis.

Jennifer J. Huang, DO¹

Judy Dawod, MD²

¹Sarver Heart Center and ²Neurology Department

University of Arizona

Tucson, AZ USA

References

1. Miller MG, Baker HL, Okazaki H, Whistant J. Central pontine myelinolysis and its imitators: MR findings. Radiology. 1988;168:795-802. [CrossRef] [PubMed]
2. Tarhan NC, Agildere AM, Benli US, Ozdemir FN, Aytekin C, Can U. Osmotic demyelination syndrome in end-stage renal disease after recent hemodialysis: MRI of the brain. AJR Am J Roentgenol. 2004 Mar;182(3):809-16. [CrossRef] [PubMed]
3. Moriwaka F, Tashiro K, Maruo Y, Nomura M. Hamada K, Kashiwaba. MR imaging of pontine and extrapontine myeliolysis. J. Computer Assist. Tomogr. 1988;12(3):446-9. [CrossRef] [PubMed] 

Cite as: Huang JJ, Dawod J. Medical image of the week: osmotic demyelination. Southwest J Pulm Crit Care. 2016;13(6):303-4. doi: https://doi.org/10.13175/swjpcc111-16 PDF

Medical Image of the Week: Diffuse Axonal Injury

Figure 1. Panel A: Non-contrast CT of the head demonstrating hyperdense foci at the gray-white junction of the cortex and subcortical white matter (red arrows). Panel B: Hyperdense focus in the pons (red arrow).

Figure 2. MRI of the brain with a gradient recall echo (GRE) sequence demonstrating more pronounced hypointense foci consistent with hemorrhage.

An 18-year-old man without any significant past medical history presented to the emergency room trauma bay as an unrestrained passenger involved in a head-on collision at 85 mph. In the emergency room, he was found to have a GCS of 6 and was intubated for airway protection. A non-contrast CT of the head demonstrated hyperdense foci in the frontal lobes at the gray-white junction (Figure 1A) and a hyperdense focus in the pons (Figure 1B) consistent with punctate hemorrhages. An MRI of the brain with a gradient recall echo (GRE) sequence (Figure 2) demonstrated more pronounced hypointense foci consisent with hemorrhage. In the setting of the patient’s deceleration injury, the summation of his clinical and imaging findings was consistent with diffuse axonal injury.

Diffuse axonal injury (DAI) is pattern of closed head injury that results in a traumatic shear injury to the neuronal axons secondary to sudden deceleration and change in angular momentum. This pattern of injury often occurs at the interface between tissues of differing density such as the gray-white junction of the cerebral cortex and subcortical white matter. DAI can also be seen in deeper portions of the brain, such as the corpus callosum and brainstem, that are relatively fixed compared with more superficial portions of the brain resulting in greater rotational/ shear stress forces focused in these locations during sudden deceleration. Visible lesions on CT often underestimate the extent of neuronal injury (often described as the “tip of iceberg”), and neuronal injury is better delineated on MRI.

Most patients present with an immediate coma necessitating intubation for airway protection.  In mild cases, patients often experience mild traumatic brain injury characterized by heachaces, mild cognitive impairment, and personality changes. In more severe cases, DAI can result in a persistent vegetative state. Treatment is supportive in all cases.

Jack Hannallah, MD¹; Tammer Elaini, MD²; Kelly Wickstrom, DO³; Rorak Hooten, MD³; Michael Habib, MD²

Departments of ¹Surgery,²Pulmonary/Critical Care, and ³Internal Medicine

University of Arizona

Tucson, AZ USA

References

1. Yanagawa Y, Sakamoto T, Takasu A, Okada Y. Relationship between maximum intracranial pressure and traumatic lesions detected by T2*-weighted imaging in diffuse axonal injury. J Trauma. 2009;66(1):162-5. [CrossRef] [PubMed] 
2. Tong KA, Ashwal S, Holshouser BA, Shutter LA, Herigault G, Haacke EM, Kido DK. Hemorrhagic shearing lesions in children and adolescents with posttraumatic diffuse axonal injury: improved detection and initial results. Radiology. 2003;227(2):332-9. [CrossRef] [PubMed] 

Cite as: Hannallah J, Elaini T, Wickstrom K, Hooten R, Habib M. Medical image of the week: diffuse axonal injury. Southwest J Pulm Crit Care. 2015;11(6):264-5. doi: http://dx.doi.org/10.13175/swjpcc121-15 PDF

Medical Image of the Week: Nocardiosis

Figure 1. Panel A: Thoracic CT scan showing enlarged left upper lobe mass. Panel B: CT scan from one month earlier showing a smaller lesion.

Figure 2. Panel A: GMS Silver stain showing Nocardia (200X magnification). Panel B: GMS silver stain showing Nocardia (400X magnification).

Figure 3. MRI Brain with arrows pointing to the lesion.

A 67 year-old man with advanced adenocarcinoma of the lung on chemotherapy and severe steroid dependent chronic obstructive pulmonary disease (COPD) was admitted for treatment of acute on chronic respiratory failure. He was admitted to the intensive care unit and required non-invasive positive pressure ventilation. He had a chest computed tomography scan (Figure 1A), with a left upper lobe mass, which was significantly larger than noted on a previous PET/CT scan (Figure 1B) from one month ago. He was placed on empiric broad-spectrum antibiotics and clinically improved. He underwent a transthoracic lung biopsy (Figure 2), which revealed the presence of organisms consistent with Nocardia on silver stain.  A brain MRI (Figure 3) showed the presence of a 4 mm enhancing lesion likely consistent with Nocardia.

Nocardiosis is a gram-positive bacterial infection caused by aerobic actinomycetes and is an important opportunistic pulmonary infection. It should be considered in the differential diagnosis of pulmonary infiltrates in immunosuppressed patients, including those with neoplasms, after organ transplantation, advanced HIV disease and those receiving chronic corticosteroid therapy or chemotherapy (1). Of importance to pulmonologists, in two reviews, COPD was a common underlying condition, representing over 20% of patients with Nocardiosis in these reports (2,3). Nocardia species are found in soil and infection is generally acquired through inhalation. The most common symptoms are fever, cough, pleuritic chest pain and headache. Common chest radiographic findings include consolidation, nodules, cavities and pleural effusions. Nocardia infections can disseminate to any organ but it has a predilection for spread to the central nervous system and patients with pulmonary Nocardia infections should have brain imaging to evaluate for cerebral dissemination. Antibiotics that are typically effective in Nocardia infections include trimethoprim-sulfamethoxazole (TMP-SMX), imipenim, amikacin, ceftriaxone and cefotaxime. However, antibiotic susceptibilities should be obtained and treatment tailored accordingly. It is recommended to treat severe systemic infections with two or three intravenous agents while awaiting susceptibility results. Treatment is usually prolonged because of the tendency of Nocardia infections to relapse or progress.  For patients with serious pulmonary infections and immunocompromised patients, duration of therapy is often at least 6 to 12 months or longer. Our patient was treated with TMP-SMX and meropenem and clinically improved. His steroids were rapidly tapered. Sputum cultures grew Nocardia farcinica.

Aarthi Ganesh MD, Muna Omar MD, James Knepler MD, and Linda Snyder MD

Department of Pulmonary and Critical Care

Banner University Medical Center

Tucson, AZ

References

1. Grigor LM, Hoover SE. Nocardiosis at a university medical center in the American southwest. Infect Dis Clin Pract 2014:22:279-82. [CrossRef]
2. Minero MV, Marín M, Cercenado E, Rabadán PM, Bouza E, Mu-oz P. Nocardiosis at the turn of the century. Medicine (Baltimore). 2009;88(4):250-61. [CrossRef] [PubMed]
3. Martínez Tomás R, Menéndez Villanueva R, Reyes Calzada S, Santos Durantez M, Vallés Tarazona JM, Modesto Alapont M, Gobernado Serrano M. Pulmonary nocardio-sis: risk factors and outcomes. Respirology. 2007;12(3):394-400. [CrossRef] [PubMed]

Reference as: Ganesh A, Omar M, Knepler J, Snyder L. Medical image of the week: nocardiosis. Southwest J Pulm Crit Care. 2015;10(5):220-2. doi: http://dx.doi.org/10.13175/swjpcc046-15 PDF