NAIL MATRIX & NAIL BED BIOPSIES
Nail Matrix Biopsy
The nail matrix consists of specialised cells that produce the nail plate. It is located at the end of the digit (finger or toe) under the skin beyond the distal phalangeal joint. It can be seen protruding as a white half-moon shape at the base of some nails. Nail matrix biopsy is a surgical procedure wherein a tissue specimen is obtained from the nail matrix. This may be undertaken to make or confirm the diagnosis of a disorder that is affecting the nail plate.
The following list describes some conditions where the procedure is undertaken:
- To distinguish inflammatory conditions like nail psoriasis and lichen planus
- To identify benign tumours like myxoid cyst, viral wart, melanocytic naevus (mole) and onychomatricoma
- To identify the cause of a longitudinal melanonychia (a pigment band in the nail plate), which may be due to a benign pigmented lesion or melanoma of the nail unit
- To diagnose squamous cell carcinoma or squamous cell carcinoma in situ
- To diagnose other nail disorders
Usually conducted under local anaesthetic the nail matrix biopsy includes the following process:
- A digital block is performed whereby sensory nerves entering the base of the affected finger or toe is numbed via injection
- The overlying nail plate may be removed for pathological examination or replaced after procedure
- A small segment of the exposed nail matrix is removed and sent for histopathological examination
All techniques involve examining the matrix for the origin of the problem. It is important that adequate and appropriate samples are taken for accurate diagnosis without damaging/scarring the matrix tissue.