Malignant Melanoma: Diagnostic Tests

Mandatory medical device diagnostics.

  • Dermoscopy (reflected-light microscopy; increases diagnostic accuracy)Note: Early detection of malignant melanoma that does not have specific dermoscopic malignancy criteria can be improved during follow-up by sequential digital dermoscopy (SDD, storage and digital analysis of the image material).In high-risk collectives, whole-body photography is an option for early detection of malignant melanoma.
  • Lymph node sonography (ultrasound examination of lymph nodes) (e.g., cervical, axillary, inguinal; abdominal lymph nodes).
    • At initial diagnosis – patients with primary diagnosis of malignant melanoma from tumor stage IB or ≥ 0.8 mm tumor thickness, no ulceration < 4 mm, with ulceration or ≥ 4 mm, with ulceration
    • For follow-up:
      • Stage IB-IIB:
        • Tumor thickness ≤ 1 mm with ulceration or increased mitotic rate or
        • Tumor thickness > 1 mm with and without tumor ulceration.
        • Tumor thickness > 4 mm without ulceration, no metastases).
        • Lymph node sonography: 1st-3rd year every six months; if SLND (sentinel lymph node biopsy) was not performed more frequently.
      • Stage IIC (tumors greater than 4 mm with ulceration) and stage III (with lymph node metastases) lymph node sonography: 1st-3rd year every three months, 4th and 5th year every six months.
  • Abdominal sonography (ultrasound examination of the abdominal organs) – for basic diagnostics.
  • X-ray of the chest (X-ray thorax / chest), in two planes – to exclude pulmonary metastases (daughter tumors in the lungs).

Optional medical device diagnostics – depending on the results of the history, physical examination, laboratory diagnostics and obligatory medical device diagnostics – for differential diagnostic clarification.

  • Confocal laser scanning microscopy (CLSM); noninvasive method for high-resolution diagnosis of tissue using reflected light technique (= ex vivo); this allows high-resolution imaging of near-surface changes with microscopic resolution of 1-3 µm in horizontal sectioning; thus, a possible alternative to conventional histology/fine tissue examination) – for differential diagnosis of melanocytic lesions, ie. i.e. between malignant melanoma, dysplastic nevi and other pigmented lesions.
  • Electrical impedance spectroscopy (EIS; measures total resistance in tissue at alternating currents of different frequencies) – can analyze changes such as atypical tissue by emitting and measuring electrical signals, indicating, for example, malignant melanoma.Indications: cutaneous melanocytic lesions with one or more clinical or anamnestic features of melanoma interpretation using a scoring system:
    • Negative score (EIS 0-3): leave as is.
    • Slightly positive score (EIS 4-6): recall after three months.
    • High positive score (EIS 7-10): excision (surgical removal of the tissue).
  • Magnetic resonance imaging (MRI) of the skull* (synonyms: cranial MRI; cMRI; brain MRI) – initial if ≥ 4 mm tumor thickness, with ulceration.
  • Magnetic resonance imaging (MRI; computer-assisted cross-sectional imaging method (using magnetic fields, i.e., without X-rays)) or computed tomography (CT) – in cases of clinical or sonographic suspicion of metastasis (formation of daughter tumors) and/or in patients with ulcerated (“ulcerating”) tumors with a tumor thickness of > 4 mm (from stage IIC onward)
  • Positron emission tomography* (PET; nuclear medicine procedure that allows the creation of cross-sectional images of living organisms by visualizing the distribution patterns of weak radioactive substances) – for staging in cases of suspected metastasis.
  • Skeletal scintigraphy (synonym: bone scintigraphy; Bone Scan) is a nuclear medicine examination – for the diagnosis of spread in stage 4.

* In stage IIC and III

Dermoscopy: five criteria for the diagnosis of melanoma in situ (MIS)

  • 1. irregular hyperpigmented areas:
    • Dark brown or black small areas in central parts of the lesion with an irregular shape that cannot be assigned to known features (dots, globules, blotches)
  • 2. regression zones
  • 3. prominent skin markings (PSM).
    • Continuous furrows pigmented lighter than the surrounding area.
    • Are typically found on the extremities
  • 4. atypical pigment network
  • 5. angled lines

Interpretation

  • 1 + 2 were in more than 50% of the lesion surface → probability of MIS was increased by 5.4 and 4.7 times, respectively
  • 1 + 3 → probability for a MIS was increased by 4.3 and 2.7 times, respectively
  • DD MIS versus invasive melanoma:
    • Extensive regression was the only indicator of MIS.
    • A blue-white haze is more indicative of invasive melanoma

Note: The criteria still need to be validated.