These huge "macrophages" can lead to permanent scarring, breathing problems and chronic coughing. The woman had smoked off and on through her teens and twenties, but was healthy - other than her worrying throat symptoms.
When researchers examined the affected person's e-cigarette, a private vaping machine used with hashish, they discovered cobalt within the vapour it launched, in addition to different poisonous metals - nickel, aluminium, manganese, lead and chromium.
'It has a distinctive and unusual appearance that is not observed in other diseases.
"This is the first known case of a metal-induced toxicity in the lung that has followed from vaping and it has resulted in long-term, probably permanent, scarring of the patient's lungs".
Professor John Britton, head of the UK Centre for Tobacco & Alcohol Studies and a consultant in respiratory medicine at the University of Nottingham, said that while cobalt could cause the disease "it is hard to see how they reached this conclusion given that no cobalt particles were detected in the lung samples from the patient".
The association warned smokers that the FDA has not found any e-cigarette to be a safe and effective tool for ending an addiction and said research has shown the devices contain risky metals and toxic chemicals including propylene glycol, heavy metals such as nickel, tin and lead, diacetyl (which can cause a unsafe lung disease often referred to as "popcorn lung"), acrolein (which causes irreversible lung disease) and formaldehyde, known to cause cancer.
An accompanying European Respiratory Society editorial on stopping smoking rejected the use of e-cigarettes as an aid, saying it was "based on well-meaning but incorrect or undocumented claims or assumptions". But that doesn't mean it should be treated lightly.
Researchers at the University of California San Francisco said the patient had hard-metal pneumoconiosis, typically found in people exposed to metals such as cobalt or tungsten used in tool sharpening or diamond polishing.
Basically, you wouldn't know you had the condition until it was too late. But the doctors did not evaluate this woman's vape pen for vitamin E acetate.
He continued: "The finding that e-cigarettes deliver heavy and hard metals to users is not a new one".
Marijuana pens may be especially unsafe, as they typically heat vape liquid about 230 degrees Celsius, while nicotine vapes heat liquid to 110 to 185 degrees C - the higher temperatures could exacerbate metal leaching.
The publication of the case study comes just as the European Respiratory Society stated that it can not back vaping as a safe aid to quitting smoking and that there is no evidence that alternative nicotine products are safe.
"They focus on the smokers and see harm reduction as a pragmatic way of reducing the devastating health effects of the tobacco epidemic". But as lung physicians, it is our job to be concerned about the substances that are inhaled into the lung, particularly those substances that can bypass our usual defense mechanisms such as these ultra-fine mists.
Last month cardiologists warned countries should consider banning vaping as they published new research suggesting it could damage the brain, heart, blood vessels and lungs.
The condition creates a distinctive pattern of damage to the lungs that results in breathing difficulties. The "ZenPen" user was presented with symptoms linked to more than 2,000 cases of vaping-related illnesses including coughing, wheezing and shortness of breath. The study authors believe that such cases will happen again and that existing cases are out there yet to be diagnosed.
The hope is that other people won't have to do the same.