Sinonasal melanoma

Definition

Primary malignant melanoma of the nasal cavity, paranasal sinuses and nasopharynx.

Epidemiology

This is a rare tumour, although the most common mucosal site of malignant melanoma, with an incidence from 0.018 to 0.051 / 105 per annum1. They account for 4% of sinonasal tract neoplasms. There is a wide age range, but this is most often a tumour of the elderly. There is a suggestion of an association with occupational exposure to formalin (not pathology staff!)1,5.

Clinical features

Patients commonly present with epistaxis, a mass or obstructive symptoms, less often with difficult breathing, pain, polyps or a nasal discharge. Occasionally, there is melanorrhoea - a "coal flecked" or brown nasal discharge, suggesting the diagnosis.

Macroscopic appearances

The majority of the tumours are polypoidal and about half appear brown or black1.

Histopathology

A minority (41/1151) of tumours show either derivation from the surface epithelium or pagetoid involvement of the epithelium. The growth pattern may be solid, spindled, peritheliomatous or meningothelial. There may be focal storiform, psueodpapilary or alveolar patterns. The majority of cases (77/1151) show pigment within neoplastic cells. There may be evidence of regression in the form of fibrosis and granulation tissue-like vessels.

The tumour cells are most often small to medium size and undifferentiated, but may be epithelioid, spindled, plasmacytoid or rhabdoid. There may be tumour giant cells with eosinophilic cytoplasm.

There is commonly an inflammatory cell infiltrate, variably composed of lymphocytes and plasma cells. A few tumours (6/1151) contain metaplastic bone.

Immunohistochemistry the immunoreactivity is similar to that of cutaneous melanomas.

 

All types

spindle cell melanomas

undifferentiated melanomas

 

S-100

93%(99/1091, 14/142, 12/143, 42/446, 14/147), 18/188

36/431

22/231

HMB-45

83%(82/1081, 12/142, 13/143, 43/446, 13/188)

28/431, more often negative than are epithelioid melanomas8

18/231

Tyrosinase

84%(84/1081, 44/446, 6/188)

31/431, more often positive than are epithelioid melanomas8

 

19/231

Melan A

75%(70/1081, 44/446, 14/188)

26/431

 

MITF

67%(62/1081, 40/446)

26/431

 

NKI/C3

9/104, 11/188

more often positive than are epithelioid melanomas8

 

Vimentin

97%(102/1051, 9/102, 14/143, 10/104, 15/188)

   

NSE

49/1061

   

CD117

37/981

   

CD99

24/1051

   

Synaptophysin

13/981, 0/143

   

CD56

8/1071

   

CD57

5/1061

   

EMA

01, 1/143

   

Cytokeratin

0/188

   

AE1/AE3 + LP34

01, 0/92, 1/143

   

Cam 5.2

01

   

Chromogranin

01

   

GFAP

01

   

CD45 (LCA)

01, 0/143

   

SMA

01

   

Muscle-specific actin (HUC1-1)

01, 0/143

   

Desmin D33

01

   

Desmin DR11

01

   

A panel of S-100, HMB-45 and tyrosinase identified all cases1.

Differential diagnosis

A combination of junctional activity and melanin is diagnostic of sinonasal melanoma.

Pleomorphic melanoma:

Small cell melanoma: "small blue round cell tumours":

Spindle cell melanoma:

Staging

A TNM staging has been suggested1:

T1: single anatomic site
T2: two or more anatomic sites
N1: any nodal metastasis
M1: distal metastasis
Stage I: T1, N0, M0
Stage II: T2, N0, M0
Stage III: any T, any N1 and/or M1

References

1Thompson, L. D., J. A. Wieneke, et al. (2003). “Sinonasal tract and nasopharyngeal melanomas: a clinicopathologic study of 115 cases with a proposed staging system.” Am J Surg Pathol 27(5): 594-611.

2Brandwein, M. S., A. Rothstein, et al. (1997). “Sinonasal melanoma. A clinicopathologic study of 25 cases and literature meta-analysis.” Arch Otolaryngol Head Neck Surg 123(3): 290-6.

3Franquemont, D. W. and S. E. Mills (1991). “Sinonasal malignant melanoma. A clinicopathologic and immunohistochemical study of 14 cases.” Am J Clin Pathol 96(6): 689-97.

4Henzen-Logmans, S. C., C. J. Meijer, et al. (1988). “Diagnostic application of panels of antibodies in mucosal melanomas of the head and neck.” Cancer 61(4): 702-11.

5Holmstrom, M. and V. J. Lund (1991). “Malignant melanomas of the nasal cavity after occupational exposure to formaldehyde.” Br J Ind Med 48(1): 9-11.

6Prasad, M. L., A. A. Jungbluth, et al. (2001). “Expression of melanocytic differentiation markers in malignant melanomas of the oral and sinonasal mucosa.” Am J Surg Pathol 25(6): 782-7.

7Regauer S. Anderhuber W. Richtig E. Schachenreiter J. Ott A. Beham A. Primary mucosal melanomas of the nasal cavity and paranasal sinuses. A clinicopathological analysis of 14 cases.APMIS 1998;106(3):403-10.

8Prasad S, Jones AS, Helliwell TR. Immunocytochemical labelling in the diagnosis of sinonasal malignant melanoma. Pathological Society January 2005, abstract 66.

This page last revised 27.12.2004.

©SMUHT/PW Bishop