27-year-old Bosnian male was admitted at the Department of Thoracic Surgery, Clinical Center of the University of Sarajevo because of the round lesion in lower right lobe, previously diagnozed on his chest X-ray. X-ray was performed because of the repetitive hemoptysis, cough and tachycardia.  
The specimen of the lung was analyzed intraoperatively. The specimen was composed of the preserved lymphatic follicles and plasma cells (Kappa & Lambda positive). Among these proliferating small lymphocytes were noticed /CD20(+), bcl-2(+) and bcl-6(-). Ki-67 staining (MIB antibody) was very low.  
The right lower lobe was surgically removed and the specimen is shown here.  
In basal parts of right lobe a big, white tumor mass (60x50x45 mm) were detected. The mass was well-circumscribed, closely related to visceral pleura.  
Microscopically, the central area of the specimen was composed of the areas with fibrosis, necrosis with proliferation of stromal (myo)fibroblasts. These changes significantly reduced the alveolar spaces. There were also some histiocytes and extravated erythrocytes with areas of fresh and old hemorrhage. Periferally, there were infiltration of small round lymphocytes with finely dispersed chromatin and proliferation of plasma cells.  
Immunohistochemistry: CK-pan (positive within epithelial cells); Bcl-2 (positive within lymphocytes), CD20 (positive), SMA (positive), Kappa (positive) and Lambda (positive). Ki-67 was very low.  
Histochemistry: PAS (negative), Pearls (positive).  
Additionally, we analyzed the patient's history of disease. He has been exposed to industrial dusts as a proffesional mechanician. No other diseases or disorders.  
Differential diagnosis: lymphoma in combination with interstitial fibrosis; rheumatoid lung disease; pulmonary hemosiderosis?  
 
I added this case to this section though not quite sure that it belongs to this category.  
Please, give your opinion whether this is inflammatory myofibroblastic tumor or intestitial fibrosis associated with lymphoma? ALK-1 staining will be performed very soon and updated here.  
 
imported on 2006-12-03 10:48:25 originally owned by semir

kunze 2006-12-03 14:43	The gross appearance of a well defined tumor and the combination of histological features (desmoid-like areas with SMA-positive spindle cells, hyalinized necroses, dense round cell infiltrates with plasma cells and lymph follicles) seem to me at the best compatible with an inflammatory myofibroblastic tumor(IMT), either inflammatory pseudotumor or true myofibroblastic tumor of unknown malignant potential. Polytypic expression of light chains may be considered as an additional argument against a lymphoma. For further characterisation of IMT an immunostain for ALK-1 is advisable.
hurwitz 2006-12-03 20:18	Dear Semir,thanks for submitting images of the macro findings and detailed clincal data. Again I would like to ask you, instead of a double submission (histopathology forum and hematopathology group) to create a referral from the histopathology forum to hematopathology, to allow everybody participating in the discussion to relate to the previous comments.   Regarding the diagnosis I agree with Dr.Kunze, considering the clinical history of exposure to industrial dusts, an inflammatory pseudotumor seems probable.I would like to see a CD3 stain as well and a high power of the kappa and lambda stain, to see if there are really positive cells.
semir 2006-12-03 20:44	Dear Dr. Hurwitz,     Thanks for your comment. Next cases, I will put up here, will follow your instructions.   Concerning the case, an inflammatory pseudotumor is a possibility. How to explain blc-2 positivity?   I will be off from my job next week and my chief (Dr. Bilalović) will capture more figures and add it here. More immunohistochemistry will be done in the coming days.
anpo 2006-12-03 21:41	Reactive B-cells (outside germinal centers) and T-cells are normally positive for Bcl-2 protein so Bcl-2 positivity in itself is not a diagnostic finding.   However, I wondered about another differential diagnosis: Castleman disease, due to high number of plasma cells, vessels and fibrosis. Nina, what do you think about it?
hurwitz 2006-12-03 23:21	Derar Anja, Castlemanns disease has indeed to be considered in the DD of inflammatory myofibroblastic tumor, however the broad sheaths of hyalinized material with plasma cells in the periphery are rather compatible with inflammatory pseudotumor than castlemanns disease where follicular structures are more prominent.
anpo 2006-12-04 23:16	I have no seen many cases myself but I have read that some of these inflammatory pseudotumors may be related to tumors of follicular dendritic cells and may be positive for EBV but I guess that is not so common in the lung but more often in abdomen. Staining for CD21 may be of use.
aorazi 2006-12-04 23:33	I totally agree with Dr.Kunze. Inflammatory pseudotumor (which I favor) versus true myofibroblastic tumor of unknown malignant potential of the lung. The numerous plasma cells and the Bcl-2 result are to be expected. Some of the IPT of the lung were indeed formerly known as plasma cell granulomas. Lymphocytes can be very numerous too. A better picture showing the SMA results (SMA.jpg is unclear to me. Vessel walls only? ), CD21 as suggested by Dr. Porwit, and of course, Alk-1 are all indicated. Very nice case.
semir 2006-12-05 12:22	I think that SMA staind myofibroblasts, not blood vessels.
semir 2006-12-05 12:24	All additional immunohistochemical stainings, you suggested, will be done in order to render the correct diagnosis (with figures posted here). Thanks for all valuable comments you have given concerning this interesting case.   Well, we just post interesting cases. That's why this section is so interesting:)
semir 2006-12-06 09:38	I have just added some more figures of immunohistochemistry analysis (kappa, lambda & AE1-AE3).
semir 2006-12-06 10:18	Additional stainings, you suggested, are also added here. Please, give more comments.
kunze 2006-12-06 12:13	Thank you, Dr. Vranic, for additional images. The SMA expression in spindle cells and the polytypic expression of light chains in plasma cells are compatible with the suggested inflammatory myofibroblastic tumor. A lack of ALK-1 in the spindle cell component argues in favor of an inflammatory pseudotumor (plasma cell granuloma) and against a true, i.e. potential malignant myofibroblastic tumor.
hurwitz 2006-12-06 13:10	Thanks, Semir for submitting this well worked-up very interesting case. I have nothing to add to the previous comments.
semir 2006-12-06 16:52	Thanks for all your comments and discussion. We can now finish discussion on this case.
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