Scalp Metastasis as the Initial Presentation of Pancreatic Adenocarcinoma: A Case Report and Review of the Literature.

Cutaneous metastases from pancreatic ductal adenocarcinoma (PDAC) are rare and typically signify advanced disease with a poor prognosis. While umbilical involvement is the most frequently reported cutaneous manifestation, scalp metastases remain extremely unusual. This case report aims to describe an uncommon scalp metastasis from PDAC and to emphasize the importance of immunohistochemical analysis in atypical cases. We report the case of a 71-year-old woman who presented initially with a painless nodule on her scalp and chronic epigastric discomfort, as well as unintentional weight loss, for at least six months. We conducted a thorough clinical examination, followed by contrast-enhanced computed tomography (CT) to stage the cancer systemically. We performed histopathological and immunohistochemical analyses on the excised scalp lesion to determine its origin. Physical examination revealed epigastric tenderness, left supraclavicular lymphadenopathy, and an asymptomatic lesion on the scalp overlying the parietal bone. CT identified a primary tumor in the pancreatic body, with liver metastases and left supraclavicular lymphadenopathy. Immunohistochemical analysis revealed diffuse positivity for cytokeratin 7 (CK7) and cytokeratin 19 (CK19) and negative staining for CK20 and pP63. Therefore, the clinical, radiological, morphological, and immunohistochemical findings were consistent with pancreatic adenocarcinoma. The patient was subsequently diagnosed with Stage IV PDAC and commenced palliative combination chemotherapy with gemcitabine and nab-paclitaxel. At the four-month follow-up, she demonstrated radiographic stability and good local healing of the scalp biopsy site. This case underscores the rarity of scalp metastasis from pancreatic adenocarcinoma and highlights the diagnostic utility of immunohistochemical markers in confirming atypical metastatic presentations. It also reinforces that persistent, enlarging, or otherwise suspicious scalp nodules require prompt evaluation and biopsy.