Australian Society of CytologyCase of the Month
February 2005 - Answer and Discussion
Melanoma- a primary cervico-vaginal case
Answer
Smear description:
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Smear was atrophic with a high yield of malignant cells. (Fig 1-2)
The malignant cells appear epitheloid with ample pale finely, granular cytoplasm. The nuclei have finely granular, clumped chromatin. Prominent anisokaryosis is present. Many cells contain macronucleoli. There are scattered cells containing fine to coarse irregular brown cytoplasmic pigment which are pathognomonic. (Fig 3-5)
The smear was diagnosed as malignant with features consistent with melanoma.
Histological description:
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Fig 6 |
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In the initial vaginal wall biopsy following the smear, pigmented cells are seen confined to the basal layers of the epithelium. They resemble those that are seen in the cervical smear. The pigment is melanin. (Fig 6)
Patient was diagnosed as having in-situ melanoma but refused treatment.
12 months later, a cervical punch biopsy and vaginal wall biopsy were taken. Both biopsies showed invasion of the stroma by malignant cells containing melanin pigments (malignant melanoma). Immunohistochemistry showed the malignant cells to be HBM45 positive. (Fig 7-8)
Discussion
Malignant melanoma is a malignant tumour arising from melanocytes, which produce the skin pigment-melanin. It usually seen arising in the skin but can occur in other sites such as mucosal surfaces, e.g. vagina, anus, oesophagus and central nervous system. It is an aggressive cancer that occurs over a wide age range although it is rarely seen in children.
Correct identification of melanoma can aid in proper therapy and early treatment.
Patients who have had malignant melanoma are at a higher risk of developing new melanomas. Therefore it is important for them to perform self-examination regularly. Malignant melanoma may appear to be a new mole/naevus, which is unpleasant-looking. Patients should apply the 'ABCD' criteria during self-examination.
A - Asymmetry. The shape of one half does not match the other
B - Border. It is irregular in outline.
C - Colour. The tone is uneven.
D -Diameter. The size is increase.
Diagnosing melanoma can be difficult in amelanotic cases where there is a lack of pigmented cells. Clinical history is useful in these cases. Immunohistochemistry, with a combination of positive reaction for S100 & HMB45, and negative for CEA or leucocyte common antigen, will be useful in these cases.
Malignant melanoma is an aggressive cancer and can metastasize quickly. Therefore, early detection can lead to early treatment and potential for cure.
Reference:
DeMay, R., The Art and Science of Cytopathology, ASCP, 1996
