Here's a recent discussion on this topic:

http://www.dailystrength.org/c/Pulmonary_Embolism/forum/15494088-pulmonary-embolism-without-dvt

There is always the possibility that the clot originated in your pelvis, as mine did. The only reason I know I had a DVT is because my doctor ordered a pelvic CT at the same time as my chest CT because I had pelvic surgery 3 weeks earlier. Without that CT, my doctor and all the hospital docs agree they would never have been able to see the clot with an ultrasound. Once you're diagnosed, they aren't likely to run another scan since the treatment for DVT is the same as PEs. I know there are other people who have had PEs without DVT, but I just wanted to throw this out there as a possibility. I am VERY grateful for my abdominal CT, as otherwise they would have probably blamed the surgery for my PEs, but I would never have known where the clots originated.

My PE appeared like that too. Nothing in the legs, no signs or symptoms of dvt. It just showed up in the lungs. It has been blamed on birth control pills.

My PE appeared in my lungs and no sign a DVT anywhere. The team who looked after me in the ER told me that this was very rare. And, since I had 0 risk factor, they are still trying to figure out why I ended with massive, bilateral PEs. I'm having the genetic testing in 2 weeks, then back on Coumadin

And they did check for a DVT in the pelvis, though not in the upper extremities, since they rarely develop in PEs.

For the most part, research suggests that 90% of PE originated as a DVT regardless of whether the DVT was located or not or if symptoms where present. The peer articles suggest that either the clot(s) were to small to exhibit classic DVT symptoms, the clot broke free and traveled to the lung, or, that the DVT was overlooked during the Doppler US.

Cavey's posting which rmb refers to discusses this and other conditions which may cause a PE:

Occasionally, other substances can form blockages within the blood vessels inside your lungs. Examples include:

- Fat can escape into the blood from the bone marrow when a long bone is fractured or during bone surgery and form an embolus.

- Amniotic fluid that is forced into the pelvic veins during a tumultuous childbirth can form an embolus.

- Cancer cells in clumps may break free into the circulation to form tumor emboli.

- Air bubbles may form emboli if a catheter in one of the large veins (central veins) is inadvertently opened to air. Air emboli may also form when a vein is operated on (such as when a blood clot is being removed) or when a person is being resuscitated (because of the force of chest compressions). An additional risk is underwater diving (see Diving and Compressed Air Injuries: Pulmonary (Lung) Barotrauma).

- Infected material may also form emboli and travel to the lung. Causes include intravenous drug use, certain heart valve infections, and inflammation of a vein with blood clot formation and infection (septic thrombophlebitis).

- A foreign substance can be introduced into the bloodstream, usually by intravenous injection of inorganic substances such as talc by injection drug users, where it can form emboli and travel to the lung."

http://www.nlm.nih.gov/medlineplus/ency/article/000132.htm

http://www.merckmanuals.com/home/lung_and_airway_disorders/pulmonary_embolism_pe/pulmonary_embolism.html

They don't know where mine showed up from either. Did they test you for antiphospholipid syndrome? Mine came back positive for that and they think that's how I got blood clots.

I had the same. they discovered the clot because i had a dull chest pain after a shoulder op. they x rayed then scanned with a dye. no swelling legs or pain in my deep vains.

Ditto...this last one came from "who knows where".

They checked me for DVTs in the leg. I told my doc later that it had to be from my arm injury, which he initially dismissed. I had fallen months prior and had significant bruising and soft tissue damage. When I could finally handle going to a chiropractor for my shoulder, the treatment left me with a lot of pain in my arm for which I used a professional quality massager. not even two days later I was in hospital. I learned that I have Factor 2, but the deep tissue massage was was bad for person's with clotting disorders. So, it can be something like an injury.

No idea where mine came from. Dr. feels strongly that it was the bc I was on. Ultrasound of my legs showed nothing. So it's a mystery.

Not sure where my came from either... Just praying they never return!

The suspects are:
a)The Depo BC shot (been on for extended # of years)
b) a leg injury where it left a big bruise that happened 6 months ago
c) possible blood disorder (but recent blood tests with hemotologist came back good as far as I know at this point)

No previous symptoms until the onset of these frightening ones in Jan 2013...which led to the diagnosis of 'Several PEs in each lung!"

My cardiologist had the deepest, most profound medical reply when I asked him point-blank what caused my massive PE's since I have no dvt's or haven't ever taken birth control......he said:
"I guess you're just unlucky!"
Sometimes even the most qualified drs. can't understand the infinite differences in our bodies.