This is a case report of a 50-year-old Filipino male, who presented with a 1-year history of constipation and an enlarging nontender left lateral neck mass, initially 2 x 2 centimeters in size. There were no reported lower urinary tract symptoms. Neck ultrasound was done showing multiple, coalescing complex foci in the left lateral neck area, the largest of which was 2.8 cm. Fine needle aspiration biopsy showed atypical epithelial cells. Weight loss, occasional hypogastric pain, continuous enlargement of the neck mass to 7 x 7.5 cm, and persistence of constipation prompted the patient to seek consult at our institution. Further work-up revealed metastatic prostatic adenocarcinoma. Abdominal computed tomography (CT) scan showed markedly enlarged lymph nodes in the retroperitoneum, dilated urinary collecting systems and ureters, a liver nodule, and lytic defects at T10 and L1 vertebrae. The prostate gland cannot be completely separated from a rectal mass. Colonoscopy showed a circumferential, nodular, friable, and edematous mass spanning 10 to 20 cm from the anal verge causing 70% partial obstruction of the lumen. Biopsy showed a poorly differentiated carcinoma positive for pancytokeratin and negative for CDX2, LCA, synaptophysin and chromogranin. Further immunohistochemistry studies were negative for CK7, CK20, TTF-1, and p63 but positive for NKX3.1 favoring the prostate gland as the primary site. Baseline prostate specific antigen (PSA) was >100.00 ng/ml.
The patient received docetaxel with prednisone, androgen deprivation therapy, and bone support therapy. After 1 month of treatment, there was drastic regression in the size of the neck mass to 4 x 4 cm. After 5 months of treatment, it further decreased to 1.5 x 2 cm in size. PSA taken after 5 months of treatment was 18.07 ng/ml. The patient is on regular follow-up in our institution and is continuing his treatment.
This case highlights the importance of considering a prostate malignancy in a male patient presenting with gastrointestinal symptoms and a neck mass even in the absence of lower urinary tract symptoms. Serum PSA, pathologic and immunohistochemistry testing are important to guide the clinician in making the correct diagnosis and treatment.