This disease with smooth muscle cell tumour in the lung and uterus has been first reported in American Journal of Pathology in 1939. (Although the pulmonary leiomyoma was reported from 1881) Since then, there are many case reports from Japan and other countries. (This may be the reason why Aj DK exposed to this patient in Japan, didn't you?)
I don't know that this disease is well-known or should be known in pulmonary fellowship training or even Pathology residency training as I am a small internist with my fund of knowledge.
From the clinical stand point, our resident 'Piyapan' has 'superb' working differential diagnoses.
I think this case was diagnosed as soft tissue tumour, low grade leiomyosarcoma metastasis from uterus or multifocal leiomyoma (too many focal though!) without awareness of uterus from clinical setting and pathology at that time if the pathologist and clinician do not aware of this disease 'Benign (but) metastatizing leiomyoma' entity.
(I do not aware this possibility of this disease as the clinical picture does not suggest metastasis disease (as Piyapan said, it is very limited to the lungs and I do not aware this disease if the history of intermittent symptoms partially corresponded with menstruation does not given and I still need to search through the internet resources for many days)
In this case, probably, the OB-GYN pathologist will be the best one who awares of this disease setting, I guess. So I will guess, again, that the concealed diagnostician should be Aj. Surang, or the others from Pathology section in OB-GYN department.
From the confusing and contradicted name of the disease, I am not sure that any of the residents will have time to read and understand that from the paper attached. So I would like to give some explaination from the molecular view.
At the time of the case firstly reported, we only have the routine pathologic examination. No immunohistochemisty techniques available at least for clinical use. So the pathology in the lung should comprised of benign-looking spindle cells or fibroid like.
There is uterine leiomyoma or uterine myoma or fibroids coexisting with the lesions in the lungs. There is no proven experiment that the tissue are the same origins or just a co-incidence. The concept of immuno markers and molecular markers for proving the origins of the tumor is feasible now. Until recently in the paper I showed, they confirmed that the origin of the benign-looking smooth muscle cell in the uterus and the lungs are the same origins and the clonal diseases. (Same X-inactivation pattern and same immuno-markers). About the telomere length, there is a theory for epithelial tumor that the telomere length shortening is one of the event occurred before it can be metastasized. For soft tissue sarcoma, there is no such confident. In this paper, the length of the telomere by FISH method is the same in both tumors site in the case investigated. We can not know the important of this finding.
To summarize, we know that it is benign looking from routine tissue diagnosis. We know that it is the same origin with the tumor in the lungs and the uteus. It seems to be hematogenous as the tumors in the lung is randomly distributed and have no perilymphatic or aerotracheal predilection. But the migration of the tissue and the pathogenesis remains to be elucidated.
