Lymphoscintigraphy: An Effective Approach to Ear Melanoma
Matthew D. Cole, BS James Jakowatz, MD, Gregory R.D. Evans, MD
From The Division of Plastic Surgery and Surgical Oncology
The University of California, Irvine
Introduction
Managing malignant melanoma of the external ear presents unique challenges.
Accounting for less than l% of the estimated 47,700 new cases of cutaneous melanoma diagnosed
in 2000, it is a relatively rare disease. Because of its low incidence, strict guidelines for its
management are less well defined. Recently, sentinel lymph node mapping, which was first
applied most reliably to cutaneous melanomas of the distal extremities, has been utilized in the
management of melanomas of the head and neck, including the ear. Because of the significant
debate regarding the efficacy and validity of utilizing sentinel lymph node mapping to manage ear
melanoma, we reviewed a population, representing all ear melanoma patients extracting data
relevant to surgical procedures utilized, sentinel lymph node mapping, and reconstructive
techniques.
Material and Methods
A retrospective chart review of a single surgical oncologist at the UCI Chao Cancer
Center was performed to identify all patients diagnosed and treated for malignant melanoma of
the external ear between 1995 and 2001. Nineteen patients were identified, of which 9 underwent
sentinel node mapping.
Results
Of the 19 patients, there were 16 males and 3 females with an average age of 65.2 years.
The decade of life in which a strong majority of the patients in this study were diagnosed was the
eighth. The average follow-up time for all patients in the study from initial diagnosis to their
most recent clinic visit was 21 months (range 12 – 79 months). All patients in this study were
evaluated at least 1 year following their initial surgical resection. Patients were followed by the
same surgical oncologist every 3 months for the first 2 years.
Of the patients in the study, superficial spreading melanoma (21.1%) and lentigo maligna
melanoma (21.1%) were the most common histologic varieties diagnosed. Ulceration was
present in the lesions of 2 (10.5%) of the 19 patients. The mean Breslow thickness at the time of
presentation was 1.75 mm with the largest group between 0 and 0.75 mm and 1.5 and 4mm. The
most prevalent location of the lesion on the ear was the helix. In 10 patients (52.6%), cartilage
was removed as part of the surgical excision. Wide local excision was performed in all patients
with an average margin of 1.31 cm. In 8 of the patients (42.1%), the wide local excision margin
was 1 cm, making this by far the most common. A partial superficial parotidectomy was
performed on 1 patient. Seventeen (89.5%) are still alive, and 2 (10.5%) have died as a result of
widespread metastatic disease.
Nine of the 19 patients received sentinel lymph node mapping. Lymphoscintigraphy and
the injection of lymphazurin dyes demonstrated a widely variable lymphatic drainage pattern.
The average number of sentinel nodes identified and removed in these 9 patients was 3.7. No
patients in the study were found, after sentinel node biopsy, to have evidence of micrometastatic
disease.
The Counts Per Second (C.P.S.) of the injected technetium Tc 99m sulfur colloid
radiolabel (along with the presence of lymphazurin dye) was the primary method for detecting
sentinel lymph nodes. The average C.P.S. of the primary injection site was 8,375. The average
C.P.S. of lymph nodes identified as sentinel lymph nodes and removed was 973.5. The most
common C.P.S. values for identified sentinel lymph nodes fell between 150 and 1000. It should
be emphasized that with this study as with others, the absolute C.P.S. is less important than a
percentage of the increase compared to background noise. We defined this percent increase at
10%.
Of the 9 patients receiving sentinel lymph node mapping, only one developed a local
recurrence. Three other patients at the time of treatment presented with previous excision and
primary closure. In these three cases, the initial treatments and surgeries were performed at an
outside facility and did not involve sentinel lymph node biopsies. The average time from initial
surgery to recurrence of these melanomas was 40 months.
A wide variety of different reconstructive techniques were utilized to close the defects
following surgical excision. Local advancement or rotational flaps were most frequent. The
average size of these defects was 10 cm2 with the largest defect measuring 24 cm2.
Discussion
Due to its intricate and complex anatomy, surgical reconstruction of the ear following
wide local excision presents unique challenges. Although appropriate margins are controversial in
the ear, at least 1 cm was utilized in all patients. The thin nature of the overlying skin of the ear
alters depth with minimal growth. Thus lesions usually present as in-situ or intermediate
thickness.
Sentinel lymph node mapping, including preoperative lymphoscintigraphy and
intraoperative mapping with lymphazurin dyes, does not affect reconstruction and is essential for
defining the basins and individual nodes draining the cutaneous melanoma of the head and neck.
We believe that both methods are critical in evaluating lymph node basins because of the
variability in this region. In the extremity, lymphoscintigraphy is used alone without the
application of lymphazurin dye. It has been estimated that sentinel lymph node biopsies, as well
as elective lymph node dissections, may be misdirected in up to 50% of cases where these
procedures are not performed. Some authors have reported difficulty with tattooing of the blue
dye. We have not found this to be a long-term problem within our population. Of the 9 patients
in our study receiving sentinel node biopsies, none had evidence of micrometastatic disease in the
sentinel lymph nodes.
The presence of high radioactive counts per second (C.P.S.) compared to baseline values
was used to identify the location of the basins draining the primary tumor site and the
combination of C.P.S. plus blue dye was used to determine the relative sentinel status of
individual nodes. It should be emphasized that with this study as with others, the absolute C.P.S.
is less important than a percentage of the increase compared to background noise. We defined
this percent increase at 10%.
The average number of sentinel lymph nodes identified and removed in our study was
3.7. This is consistent with other studies. It seems that within this study we have employed a less
conservative approach to designating nodes as sentinel. It may be the ear’s distinctly ambiguous
and variable lymphatic drainage pattern, when compared to other body locations, that necessitates
a more liberal standard when deciding which lymph nodes to remove. It also may simply
represent a more aggressive approach on the part of our surgeons to ensure that easily removed
lymph nodes are not unwisely missed.
In terms of patterns of lymphatic drainage, our study is in line with the conclusions of
others; namely that the lymphatic drainage of the ear is highly variable and unpredictable. This
conclusion further reaffirms the important role that preoperative lymphoscintigraphy plays in
attempting to define which lymph node basins receive lymphatic drainage from a primary tumor
site, since generalizations concerning the most common patterns of lymphatic drainage are
difficult to define.
Managing malignant melanoma of the ear requires a consideration of the need to
aggressively treat suspected advanced disease with therapies such as radical neck dissection and
immunotherapy. A balance also exists between the need for wide local excisions with curative
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margins sufficient to prevent local recurrence, and the complex repairs of expansive surgical
defects in a structure that presents a great reconstructive challenge. This study has presented our
groups experience in treating ear melanoma from the perspective of curative resection and staging
as well as plastic surgical reconstruction to maximize functional and cosmetic outcome.
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