Pathology · patient case question
A biopsy is taken of the discrete blue-gray gingival macule. Which microscopic finding would you expect?
Patient case: Bronzed Skin and Darkened Gingiva
Patient: 45-year-old female
Chief Complaint: “I’ve been exhausted for months and my gums look darker than they used to.”
Background: Progressive fatigue, 12 lb unintentional weight loss, lightheadedness on standing, strong craving for salty food. No formal medical diagnosis; has not seen a physician in 4 years.
Medications: None
Vital Signs: BP 92/58 mmHg · HR 96 bpm · RR 16 · T 98.4°F
Findings: Diffuse bronze pigmentation of the skin, including areas never exposed to sun. Patchy brown macular pigmentation of the buccal mucosa and attached gingiva. Separately, a discrete 4 mm blue-gray macule in the left mandibular attached gingiva adjacent to a large restoration in #19. Panoramic radiograph obtained.
Show answer and explanation
Correct answer: C. Fine black granular material along collagen bundles with a foreign-body reaction
- A. Incorrect. That describes a blue nevus. It is a genuine consideration for a blue-gray oral macule, but the associated radiopacity next to a large amalgam restoration makes tattoo far more likely here.
- B. Incorrect. That describes a varix, which appears as a soft, compressible blue-purple papule that blanches on diascopy, most often on the ventral tongue or lower lip. It would not be radiopaque.
- C. Correct. This is an amalgam tattoo. Metallic particles deposit along collagen fibers, basement membranes, and vessel walls, and larger fragments provoke a chronic foreign-body giant cell reaction. It is the diagnosis that matches both the clinical blue-gray color and the radiopacity seen on the panoramic.
- D. Incorrect. That describes an oral melanotic macule — a flat brown lesion from increased melanin without melanocytic proliferation. It is brown rather than blue-gray and produces no radiopacity.
Note: Clinical rule: a blue-gray macule with a matching radiopacity needs no biopsy. Biopsy is reserved for pigmented lesions with no radiographic correlate, since melanoma is the lesion you cannot afford to miss.