acrometastasis in the third proximal phalanx of the left hand from primary lung malignancy: a rare case report

Acrometastasis, described as metastasis of cancer to bones distal to elbow or knee, is a rare clinical diagnosis. it represents around 0.1% of all bone metastases, making it a unusual clinical manifestation, especially as initial findings. acrometastasis is a sign of very advanced malignancy process. this case report present a 57-year-old javanese man sought treatment for a progressively enlarging mass in his left third finger, alongside intermittent shortness of breath. initial imaging suggested a primary malignant bone tumor. initial workup diagnosis were primary bone tumor of third proximal phalanx of the left hand. biopsy of the finger mass then confirmed it was metastatic adenocarcinoma, with immunohistochemistry indicating a lung primary origin. the final diagnosis was acrometastasis of the left third finger from a primary lung adenocarcinoma. bone metastases are generally prevalent especially from lung origin, acrometastases—those affecting the extremities—are exceedingly rare, accounting for only 0.1% of all bony metastases. it is even more unusual for acrometastasis to be the initial presenting symptom of lung cancer, often mimicking more benign conditions and delaying diagnosis. lung carcinoma, particularly adenocarcinoma, is the most common primary source of acral metastases due to its direct arterial access. treatment for acral metastasis ranges from amputation to palliative measures such as radiotherapy, bisphosphonates, and chemotherapy, depending on the tumor’s stage and extent. acrometastasis is usually found as a late-stage diagnosis after other common metastases sites were diagnosed, but its earlier diagnosis may help determine the progression of the disease earlier and treat it accordingly.