Implications of popliteal lymph node detected by sentinel lymph node biopsy.
BACKGROUND
Although there is lymphatic flow into the popliteal fossa from a skin tumor located in the lower leg, popliteal metastasis is extremely rare. Recently, sentinel lymph nodes outside traditional nodal basins have been identified. This study investigated the incidence of sentinel nodes in the popliteal region and the indication for biopsy.


METHODS
Fourteen patients with various skin cancers involving the lower extremities (nine melanomas, four squamous cell carcinomas, and one sweat gland carcinoma) underwent lymphoscintigraphy and excision with sentinel lymph node biopsy.


RESULTS
In all 14 patients, hot spots showed accumulation in the groin region. Five of 14 patients (36%) demonstrated popliteal sentinel nodes in addition to the inguinal nodes. Three of five popliteal sentinel nodes were histologically studied. A patient with acral melanoma demonstrated micrometastasis of melanoma cells in a popliteal node but not in the groin node.


CONCLUSIONS
This study demonstrates that sentinel lymph nodes located in the popliteal fossa are frequently detected by lymphoscintigraphy and that biopsy should be performed if popliteal nodes are identified.
Hatta
Naohito
N
Department of Dermatology, Kanazawa University School of Medicine, Takara-machi, Kanazawa, Japan. hattanao@tch.pref.toyama.jp
Morita
Reiji
R
Yamada
Mizuki
M
Takehara
Kazuhiko
K
Ichiyanagi
Kenji
K
Yokoyama
Kunihiko
K
D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D005260:Female; D006119:Groin; D006801:Humans; D007866:Leg; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000473:pathology*