Year : 2008 | Volume
: 51 | Issue : 4 | Page : 485--488
A clinicopathological study of malignant melanoma with special reference to atypical presentation
Subhalakshmi Mukhopadhyay1, Sambuddha Ghosh2, Dutta Siddhartha3, Pradip K Mitra1,
1 Department of Pathology, Midnapore Medical College, West Bengal, India
2 Regional Institute of Ophthalmology, Midnapore Medical College, West Bengal, India
3 Department of Gynecology, Midnapore Medical College, West Bengal, India
BB 41/8, Salt Lake City, Kolkata
Malignant melanoma is a tumor of melanocytic origin. Lymphatic and hematogenous metastases are common in this condition. Retrospective analysis was performed in 16 consecutive cases diagnosed histopathologically as malignant melanoma at the pathology department of a medial college in eastern India. 75% of the patients were male; majority of them was in their sixth decade. All (100%) the lesions were pigmented. The primary site was known in all cases, except two (12.5%). Out of the 14 cases with known primary site 11 (78.57%) were cutaneous melanomas, including one arising in labia minora, two (14.29%) were ocular and one (7.14%) was vaginal in origin. Among cutaneous melanomas, superficial spreading type was the commonest variety and mixed population of epithelioid and spindle cell was the commonest histopathological pattern. The commonest grade of invasion was grade III (Clark«SQ»s). The clinical presentation of the case of vaginal melanoma and the two cases of secondary melanomas, including the one with obscure primary tumor, were bewildering and hence are discussed separately.
|How to cite this article:|
Mukhopadhyay S, Ghosh S, Siddhartha D, Mitra PK. A clinicopathological study of malignant melanoma with special reference to atypical presentation.Indian J Pathol Microbiol 2008;51:485-488
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Mukhopadhyay S, Ghosh S, Siddhartha D, Mitra PK. A clinicopathological study of malignant melanoma with special reference to atypical presentation. Indian J Pathol Microbiol [serial online] 2008 [cited 2020 Mar 30 ];51:485-488
Available from: http://www.ijpmonline.org/text.asp?2008/51/4/485/43736
Incidence of melanoma and its mortality rates are increasing in most countries throughout the world where they are being recorded.  According to World Health Organization, the number of melanoma cases worldwide is increasing faster than any other cancer.  Besides skin, melanoma may arise in any location where melanocytes are found. Cutaneous malignant melanoma commonly occurs in light-skinned persons of the West and Australia. Although it is a widely studied tumor, documentation of its incidence and clinical presentation in the dark skinned individuals of India or Asia is far from complete. The aim of this study is to document the pattern of clinicopathological features of malignant melanoma cases attended in a medical college in eastern India with special reference to an atypical presentation that masquearded as some other condition.
Materials and Methods
Retrospective analysis was conducted on the 16 consecutive cases diagnosed histopathologically as malignant melanoma between April 2000 and March 2005 in the department of pathology of a medical college in Kolkata, India. The data of the patients were obtained from hospital records. Clinicopathological types of cutaneous lesions were determined by the attending dermatologists on the basis of the following criteria: lesions with definitely elevated surface with or without ulceration were defined as nodular lesions, flat lesions with variegated appearance were defined as superficial spreading lesions, flat lesions with uniform dark pigmentation limited to acral parts only were termed as acral lentiginous and flat lesions, gradually growing, tan- to black-colored lesion situated on the areas exposed to sunrays was defined as lentigo maligna. Histopathological parameters of the tumors were evaluated for cell type, invasion (based on Clark's system), pigmentation, mitotic activity and dermal lymphocytic infiltration. Apart from routine haematoxylin-eosin staining of the tissue sections, immunohistochemical staining by S-100 stain was performed in six cases including the case of vaginal melanoma.
Sixteen cases were included in the study. Twelve (75%) of them were male and four (25%) were female; the age range was 32-80 years. Five (31.25%) patients were in sixth decade, 4 (25%) were in seventh decade, 3 (18.75%) in fifth decade, 2 (12.5%) in third decade and 1 (6.25%) each in the fourth and eighth decades. Primary site was known in all cases, except two (12.5%) cases. Out of the 14 cases with known primary site, 11 (78.57%) were cutaneous melanoma, including one arising from labia minora; two (14.29%) originated from ocular and one (7.14%) from the vaginal tissue. At the time of presentation, 9 (56.25%) patients showed no clinical evidence of metastasis, 5 (31.25%) had metastasis to lymph nodes and 1 (6.25%) each had metastasis to liver and soft tissues. Four (36.36%) cases of cutaneous melanoma developed in preexisting melanocytic lesion. In 6 (54.54%) cases of cutaneous melanoma, lesions were in the lower extremity, in two cases (18.18%) in upper extremity, in one case each (9.1%) on face, back and labia minora [Table 1]. Out of 11 cases of cutaneous melanoma, 6 (54.54%) were of superficial spreading variety followed by 4 (36.36%) of acral lentiginous and one (9.1%) of nodular variety. Lentigo maligna was absent in our series. All (100%) were pigmented lesions. Eight (72.72%) cases of cutaneous melanoma revealed mixed epitheloid and spindle cell-type, while only epitheloid cells were present in 2 (18.18%) and only spindle cells was present in one (9.1%) case. Mitotic activity was present in 3 (27.28%) cases of cutaneous melanoma. When graded for the level of invasion by using Clark's system, 4 (36.36%) cases showed grade III invasion, 2 (18.18%) each were in grade I, II and IV. One (9.1%) case was in grade V [Table 2]. Both the cases of ocular melanoma were male patients in the seventh decade of life, one (50%) each of them arising from choroidal and conjunctival tissues. The eye with choroidal melanoma revealed scleral invasion.
The series includes melanomas of skin of ocular origin and a rare case of primary vaginal melanoma. Cutaneous melanoma was the most common type of melanoma and superficial spreading type was the most common type of cutaneous melanoma in this series (54.54%) as expected because in India, superficial spreading melanoma and nodular melanoma are commonly found,  acral lentiginous malignant melanoma being rare.  On the other hand, Vayer et al. found that acral lentiginous-type melanoma is the most common variety (66%) among all other cutaneous melanomas.  In our series however, acral lentiginous-type was the second most common (36.36%) variety. Majority of the patients in our series came seeking medical care for the first time with invasive lesion (cases in Clark grade III and IV), which may be the reason for a short survival period in those patients. In one series, non-visceral metastases were associated with a median survival of 12-15 months and distant metastases were associated with 6-9 months survival.  Lymph node metastases were the commonest form of metastases of cutaneous melanoma in our series. Preexisting lesions were present in both superficial spreading and acral lentiginous types in equal numbers, thereby excluding any association. Three out of four of these lesions presented for the first time with deeper invasion, possibly because the transformation was silent and escaped notice. Mitotic activity had no association with invasiveness or tumor behavior in this series.
Three cases of our series require special mention. Of them, metastases were the only manifestation in two cases at the time of presentation, although one of them had a history of an already removed primary tumor. In another case, vagina was the site of primary lesion.
Case 2 masqueraded as inguinal lymphadenitis. It presented with a 5 cm 5 cm swelling in the left inguinal region; approximately 2 ml of brownish fluid was obtained on aspiration. FNAC was suggestive of metastases from adenocarcinoma as the smear showed groups of malignant epithelial cells in clusters on a dirty background. Pigment containing cyst macrophages were also present [Figure 1], whose significance could not be understood at that time. Old hemorrhage in the metastatic mass was thought to be the possible explanation of pigment-laden macrophages. Excision of the mass was performed; it was a cystic swelling of 3 cm 2 cm size; margins were apparently made up of fibroconnective tissue with no definite cyst lining. The cyst contained dirty brown thin fluid. Histopathology revealed malignant melanoma with a tumor mass in the soft tissue deep to skin and subcutaneous tissue without any involvement of the overlying skin. No lymph node structure was present. The diagnosis was either soft tissue metastases of a hidden primary melanoma or primary soft tissue melanoma. Pressure necrosis in the tumor was the cause of this cystic change.
In case 11, the metastatic lesion was mistaken for an abscess, as the attending surgeon was not informed about the history of removal of the primary tumor 6 months before. The lesion masquerading as an abscess was present for approximately seven days; it was situated behind the thigh just above the popliteal fossa. It was tender and the overlying skin was hot with no obvious color change. The warmth was not because of inflammation, but because of the increased vascularity of the area. When drainage was attempted, he bled severely and amputation had to be done at the level of the junction of upper two-third and lower one-third of the thigh as other measures failed. On gross examination of the amputated extremity, a cavitary lesion of approximately 3 cm diameter was observed at the back of the thigh. The cavity was full of blood clots; no color change was noted in the overlying skin. Histopathology of the tissues forming the wall of the cavity revealed pigmented and nonpigmented epithelioid malignant cells in reticular formation, which are suggestive of the diagnosis of malignant melanoma. Clinical reevaluation and correlation revealed that the patient underwent a minor surgery a few months back for a small swelling under the right sole. Histopathology report of the previous lesion confirmed that it was malignant melanoma. Review of the histopathology slides of the previous lesion and the soft tissue mass led to the conclusion that the lesion masquerading as abscess was actually soft tissue metastases from the acral lentiginous melanoma of the sole that had appeared after the removal of the primary tumor. In cases of cutaneous melanoma, cutaneous and subcutaneous metastases located between the primary site and the regional lymph node, also known as in-transit metastasis are the common findings.  In-transit metastases also may be seen after the resection of sentinel lymph node.  In approximately 4%-10% of the patients who present initially with metastases of melanoma, no primary tumor is ever found.  In the case of melanoma, late metastases are rare, though it occurs, even as late as ten years.  Distant metastasis is commonly found in the liver, lungs, gastrointestinal tract, bone and central nervous system. In this series, liver was the most common site for visceral metastases.
Case 15 of the series presented with postmenopausal bleeding occurring for the last one month. Examination under anesthesia revealed generalized thickening of the anterior vaginal wall and a pigmented lesion extending over two-thirds of the anterior vaginal wall extending up to posterior fornix. Histopathology revealed a necrotic tumor composed of polygonal cells. At places, there were alveolar or polygonal pattern and abundant melanin pigments. Tumor cells showed S-100 immunohistochemical staining positivity [Figure 2]. Metastases were present in the liver. She died within two months in spite of receiving high dose rate (HDR) remote afterloading brachytherapy.
Malignant melanoma of the vagina is a rare malignancy associated with high risk of recurrence, distant metastasis and short survival time.  Malignant melanomas of female genitalia comprise 3-7% of all melanocytic tumors, vulval skin being a common site (1-2%).  Of all the vulval malignant neoplasms, melanoma comprises 3.6%-10%.  Superficial spreading melanoma is the most common type of melanoma found in vulva;  the same is also observed in our series.
In our series, a rare case of conjunctival melanoma has been included. It was a perilimbal interpalpebral pigmented growth on the bulbar conjunctiva.
Conjunctival melanoma occurs 1/40 th as often as choroidal melanoma and occurs 500 times less often than cutaneous melanoma.  Incidence of external ocular melanoma, which includes melanoma of eyelids and conjunctiva, reduces with increase in latitude while incidence of internal ocular melanoma increases with increase in latitude. 
This series documents clinicopathological features of melanoma, a relatively rare but increasingly occurring disease. We report melanoma cases that have an unusual presentation and that leads to diagnostic confusion. Although the number of cases in our series was 16, it is difficult to obtain a large number of cases in any one center due to relative rarity of the tumor.
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