Chronic expanding hematoma (CEH) is defined as a hematoma that gradually increases in size over one month or longer. Typically, CEH affects soft tissues and subcutaneous layers. Only a few studies have documented CEH of the upper limbs 1) , and CEH of the digits is extremely rare. Here, along with relevant literature, we report a rare case of CEH of the dorsum of the thumb.
Case presentationThe patient was an 81-year-old woman with no significant family history. She was on antiplatelet medications (ethyl icosapentate and limaprost alfadex) for hyperlipidemia and asymptomatic cerebral infarction.
Current medical historyA subcutaneous mass accompanied by pain developed in the right thumb approximately two years prior to the initial examination. However, it is unclear whether the patient has a history of trauma. She visited a local clinic because of the gradual enlargement of the mass. Ultrasonographic findings suggested angioma; therefore, the patient visited our department for further examination and treatment.A subcutaneous mass with a major axis of approximately 20 mm was found on the radial side of the center of the proximal phalanx of the dorsum of the right thumb. The overlying skin was smooth and pale bluish purple (Fig. 1). The mass was elastic and displayed poor mobility on palpation. Ultrasonography revealed an irregular, slightly hypoechoic subcutaneous mass (approximately 15 mm) with relatively clear boundaries above the proximal phalanx. Power Doppler