Hypertrophy and hyperplasia are common medical terms. Doctors, like lawyers, tend to come up with single words or short phrases to summarize important concepts. Both professions develop a lexicon that is sometimes impenetrable to the uninitiated.
Fortunately, hypertrophy and hyperplasia are simple concepts. In hypertrophy, cells increase in size. In hyperplasia, cells increase in number:
Axial images of the thumb reveal an oval mass (red arrow) corresponding to the clinically palpable abnormality. The mass has a tubular-appearing T2 hyperintense rim which enhances following the administration of gadolinium.
(A) Sagittal and (B) Coronal intermediate weighted images with fat saturation through the lesion reveal hypointense material within the center of the lesion.
Here are images from a different patient, also with a thumb mass:
Multiple images through the lesion reveal that this lesion has an appearance almost identical to the first, with a tubular T2 hyperintense rim that enhances following the administration of gadolinium (red arrows). This lesion also has hypointense material more centrally (green arrows).
Both of these lesions were excised, and were confirmed to be cases of intravascular papillary endothelial hyperplasia (IPEH), also known as Masson's tumour. An excellent description of this condition is provided by Dr. Sampurna Roy.
IPEH is a reactive condition representing an unusual form of organizing thrombus. Masson's tumour may either occur in pure form (primary), as a focal change in a preexisting vascular lesion (hemangioma, pyogenic granuloma, or vascular malformation) and rarely in an extravascular location as a result of organization of a hematoma.
The lesion may occur in any blood vessel in the body, but is commonly located on the fingers, head and neck and trunk. It is typically seen as a small (less than 2 cm in diameter), firm, blue or purple nodule. This lesion has been reported to occur deep in the body, including the liver (J Korean Med Sci 19:305, 2004) and renal sinus (Jap J Clin Oncol 27:433, 1997)
Multiple small, delicate papillary structures project into the lumen and these are associated with thrombus. These projections and associated thrombus presumably give rise to the T2 hypointense material seen in the central aspect of the lesions presented here.
This lesion has an excellent prognosis and is usually cured by simple excision.
If you see a hand lesion with a tubular T2 hyperintense rim that enhances, with a T2 hypointense center, one should think of the diagnosis of IPEH.
Vic David MD