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Clinical Example: Flashlight transillumination for tumor diagnosis
Imaging has come a long way in recent
years, but there remains a middle ground between physical examination and
MRI - light transillumination. I regularly use a penlight in the office
as a low tech but often helpful diagnostic tool. Tumors fall into four
groups based on opacity relative to surrounding tissues:
|
Finding
|
Likely pathology in the hand or finger |
| Bright: more transparent than surrounding
tissues. The area lights up more than the surrounding tissues. |
Ganglion cyst filled with clear liquid |
| Equal: the area lights up to the
same degree as surrounding tissues. |
Lipoma
Neurolemmoma |
| Indeterminate: the area seems darker
than surrounding tissues to a variable degree. |
Giant cell tumor
Inclusion cyst
Thick skin callus |
| Dark: the area is clearly opaque,
creating a shadow effect. |
Aneurism
Hemorrhage into a ganglion cyst
Calcification
Gouty tophi
Osteophyte |
|
| Click on each image
for a larger picture |
| Case 1: Mass arising a year after nail
bed excision and skin graft for nail bed squamous cell carcinoma. |
 |
| Xrays show discrete calcification in
the area, consistent with heterotopic ossification. |
 |
| Transillumination appearance, dark
or opaque. |
 |
| Case 2: Firm mass arising just distal
to the PIP joint, fixed to deep structures. |
 |
| Xray shows a contour change of the
middle phalanx deep to the tumor. |
 |
| Transillumination is indeterminate,
slightly darker than surrounding tissues. |
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| Intraoperative finding: classic giant
cell tumor, arising from the PIP collateral ligament. |
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| Case 3: Painless dorsal middle phalanx
mass. |
 |
| A standard plastic disposable flashlight
is fine, but better if the tip is wrapped in opaque electrical tape to
limit the light flare through the sides of the flashlight. |
 |
| Bright transillumination confirms the
diagnosis of ganglion cyst. Treatment: observation. |
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| Case 4: similar to case 3. |
 |
| Flashlight |
 |
| A picture of the illumination is more
obvious with the finger placed on a lit transparency light box. |
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| Case 5: illustrating the use of transillumination
even in the darg skinned patient. Chronic dorsal distal phalanx tumor and
concave nail deformity: |
 |
| Flashlight: |
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| Transillumination: clearly a mucous
cyst. |
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| Intraoperative excision and joint debridement,
demonstration of the deep pull out sutures used to close the deep skin
layer of an eponychial splitting incision: |
 |
| Healed. |
 |
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American
Society
for
Surgery
of the
Hand
assh.org
The Best
Resource
For Your
Hands,
Period.
|
