A 66-year-old woman presented to the emergency room with pain and bluish discoloration of her left great toe for the past 2 days. She had no history of trauma to the toe or of peripheral vascular disease. She also complained of intermittent abdominal pain for the last 5 months and unintentional weight loss of 8 pounds.
On examination, the left hallux was bluish-purple (Figure 1) with an acral distribution (ie, more affected distally). The other extremities were not affected. There was no difference in temperature between her feet, and distal sensation and peripheral pulses were intact.
Acrocyanosis of the left hallux with an acral distribution.
Vascular disease was suspected, and the patient was started on systemic anticoagulation. However, chest computed tomography (CT) and conventional angiography showed no aortic disease; vessels were of normal caliber, and no distal filling defects were noted.
A routine evaluation with complete blood cell count, peripheral smear, renal function testing, and urinalysis with eosinophil smear was also unrevealing. An extensive investigation followed, including serum complement testing, assays for antinuclear, antineutrophil cytoplasmic, and anti-Sjögren syndrome A and B antibodies, cryoglobulin testing, and hepatitis B and C virus serology, as well as screening for syphilis and lupus anticoagulant, anticardiolipin, and beta-2 glycoprotein antibodies. The results for all these tests were also unremarkable.
Results of coagulation testing and venous duplex ultrasonography of the legs were normal, and electrocardiography and echocardiography showed no signs of valvular vegetation, myxoma, or patent foramen ovale.
Given our patient’s age, abdominal pain, and weight loss but negative vascular evaluation, we considered a diagnosis of paraneo-plastic acral vascular syndrome. Abdominal CT revealed a tumor of the pancreatic head with multiple liver lesions, and cytologic study confirmed pancreatic adenocarcinoma.
DISTANT MARKERS OF MALIGNANCY
Causes of blue toe syndrome to consider in the differential diagnosis include arterial thromboembolism, vasoconstrictive drug use or disorders, vasculitis, and venous thrombosis.1 These are common and deserve prompt investigation. However, if they are ruled out, a peripheral acral vascular syndrome should be considered. These syndromes present as Raynaud phenomenon, gangrene, or acrocyanosis of the fingers or toes with underlying neoplasia. Unusual features such as sudden onset in a patient over age 50, an acral distribution, and associated symptoms such as unrelated pain and weight loss should spark concern for underlying malignancy.
Paraneoplastic syndromes are defined as signs and symptoms that present distant from the site of malignancy. Dermatoses as markers of internal malignancy are well-established but perplexing clinical entities whose exact causes remain unknown.2
Paraneoplastic acral vascular syndrome is associated with certain cancers, predominantly adenocarcinoma and metastatic disease.3 As in our patient, it usually precedes or is present at the time of diagnosis of internal malignancy. Paraneoplastic dermatosis as the presenting sign of pancreatic cancer is uncommon, and a search of the literature found 1 case report of acral vascular syndrome.4 Paraneoplastic dermatoses also include necrolytic migratory erythema, Leser-Trélat syndrome, and acrokeratosis paraneoplastica (Table 1).
Paraneoplastic dermatoses associated with internal malignancy
Paraneoplastic dermatoses are well recognized as harbingers of metastatic disease.5,6 Our patient’s story demonstrates need for a thorough diagnostic investigation.
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