|Year : 1995 | Volume
| Issue : 3 | Page : 140-142
Study of formaldehyde-induced fluorescence in cutaneous melanomas and naevi
AB Harke, PG Thakar, SD Deshmukh
A B Harke
Source of Support: None, Conflict of Interest: None
We have investigated 16 cases of cutaneous malignant melanomas and 34 cases of various types of neavi for formaldehyde-induced fluorescence. All cutaneous malignant melanomas (100%), but only two out of 34 naevi (5.88%) showed FIF positivity. The significance of this finding as a predictor of biological behaviour is discussed
Keywords: Fluorescence, Cutaneous melanoma, Naevi
|How to cite this article:|
Harke A B, Thakar P G, Deshmukh S D. Study of formaldehyde-induced fluorescence in cutaneous melanomas and naevi. Indian J Dermatol Venereol Leprol 1995;61:140-2
|How to cite this URL:|
Harke A B, Thakar P G, Deshmukh S D. Study of formaldehyde-induced fluorescence in cutaneous melanomas and naevi. Indian J Dermatol Venereol Leprol [serial online] 1995 [cited 2020 Jan 22];61:140-2. Available from: http://www.ijdvl.com/text.asp?1995/61/3/140/4180
| Introduction|| |
The histologic diagnosis of cutaneous malignant melanoma is relatively easy in the majority of instances, as also its differentiation from naevi. On occasions, it is difficult to interpret the malignant potential of some of the naevi, specially of the junctional and compound types.
The diagnostic significance of the technique of formaldehyde-induced fluorescence on formaldehyde-fixed, paraffin-embedded tissue sections has been studied in melanomas and other lesions., In this technique the malignant melanoma shows yellowish fluorescence, which is absent in benign melanin-containing lesions and other malignant lesions like undifferentiated carcinoma, cutaneous histiocytic lymphoma and Paget's disease of the skin. The fluorescence phenomenon is based on the action of formaldehyde on intracellular biogenic amines such as dopamine, epinephrine, norepinephrine and melanin.
| Materials and Methods|| |
Sixteen cases of primary cutaneous malignant melanoma and thirty-four various types of naevi diagnosed over a period of 5 years were retrieved from the files of the Surgical Pathology Department of B J Medical College and Sassoon General Hospitals, Pune.
All tissues were fixed in 4% formaldehyde, routinely processed and embedded in paraffin. Five micron thick sections were cut and mounted on cleaned glass slides. The slides were incubated in the oven (56°C) for 30 minutes and deparaffinised by immersion in the sequence of xylene, ethylalcohol and water. The unstained sections were mounted with synthetic mounting medium, DPX (Di-n-butyl pthalate and xylene, BDH chemicals).
Ten cases of malignant melaomas were examineda before and after sodium borohydride reduction as described by Corrodi and others, to confirm the monoamine specificity of fluoresence.
All sections were examined by using a standard fluorescence microscope (Carl Zeiss) equipped with a M35 camera body, HBO 50W mercury lamp, band pass excitation filter BP 450-490, barrier filter LP 520 and plain objectives. The room was kept dark.
Cells showing yellowish fluoresence were read as positive. Positive fluorescence was graded as weak, moderate or strong based on the intensity of fluorescence.
Formaldehyde-fixed tissue from an autopsy of a known case of malignant melanoma was treated as the positive control and an unfixed tissue (without formaldehyde) of a frozen section from a case of malignant melanoma and formaldehyde-fixed normal skin biopsy was treated as the negative control.
| Results|| |
All the sixteen cases of cutaneous malignant melanomas revealed yellowish fluorescence [Figure - 1]. The formaldehyde induced fluorescence of all melanomas tested showed quenching on sodium borohydride exposure.
Out of 34 naevi, only two (5.88%) showed focal formaldehyde-induced fluorescence. The break-up of the lesions and their FIF positivity or negativity is depicted in [Table - 1].
Twenty intradermal naevi [Figure - 2], one systematised epidermal naevus, one neuronaevus and one Naevus sebaceous of Jadassohn More Details were negative for FIF. One of four junctional naevi (25%) and one of seven compound naevi (14.29%) showed moderate fluorescence.
In the cases of melanoma, cases which revealed strong fluorescence disclosed a diffuse pattern, while in cases where fluorescence was weak to moderate there was relatively prominent fluorescence of individual structures such as nucleoli, nuclear membrane and cytoplasm. Melanoma cells in the superficial portion of the dermis and the tumour showed stronger fluorescence. Within the same tumour, there was variation in the intensity of fluorescence in different parts. Normal epidermal melanocytes were negative.
Reticulin, elastic fibres, stratum corneum and erythyrocytes displayed green fluorescence (negative FIF) of varying brightness, which was distinct from the yellowish positive FIF of a malignant melonoma.
| Discussion|| |
The induction of fluorescence by formaldehyde in the case of melaoma cells in a culture was well known, but its potential in diagnostic histopathology has only been recently realised. It is also useful as a diagnostic method in cases of amelanotic melanoma and for differentiating malignant melanoma from Paget's disease. The nature of the moiety that is fluorescent after treatment with formaldehyde is not fully understood. Conversion of an intermediate metabolite in the biosynthesis of amines in the cell to 3-4-dihydroisoquinolines has been implicated.
In the present study, positive FIF was observed in all 16 case of cutaneous malignant melanoma. Earlier workers have found FIF positivity ranging from 70 to 84% in melanomas studied from different sites in the body, either primary or metastatic.,
All intradermal naevi were FIF-negative, an observation that is in accordance with their benign biological behaviour. One case of junctional naevus (out of four) and one of compound naevus (out of seven) showed positive FIF in this series. Interestingly, Inoshita et al and Dalal et al reported positive FIF in three out of five and two out of eight compound naevi studied, respectively.
FIF positivity in naevi possibly indicates their malignant potential. However, the long latent period and wide local excision initially, makes the follow up of these cases difficult. Needless to say, those naevi showing positive FIF must be followed up with sustained enthusiasm over the years to substantiate their malignant potential.
| References|| |
|1.||Dalal Bl, Slinger RP. Formaldehyde-induced fluorescence in melanomas and other lesions. Arch Pathol Lab Med 1985;109:551-4. |
|2.||Inoshita T, Youngberg GA. Fluorescence of melanoma cells: A useful diagnostic tool. Am J Clin Path 1982;78:311-5. [PUBMED] |
|3.||Corrodi H, Jonsson G. The formaldehyde fluorescence method for histochemical demonstration of biologic amines: A review of methodology. J Histochem Cytochem 1967;15:65-78. |
|4.||Corrodi H, Hillarp NA, Jonsson G. Fluorescence methods for the histochemical demonstration of monoamine III. Sodium borohydride reduction of the fluorescent compounds as a specificity test. J Histochem Cytochem 1964;12:582-6. [PUBMED] |
[Figure - 1], [Figure - 2]
[Table - 1]