|Year : 2018 | Volume
| Issue : 3 | Page : 709-711
Sinonasal malignant melanoma with metastasis: Immunohistochemistry meeting the diagnostic challenge
Prajwala Gupta, Minakshi Bhardwaj
Department of Pathology, Post Graduate Institute of Medical Education and Research and Dr. RML Hospital, New Delhi, India
|Date of Web Publication||12-Jun-2018|
Dr. Prajwala Gupta
40/22, Ground Floor, East Patel Nagar, New Delhi - 110 008
Source of Support: None, Conflict of Interest: None
Sinonasal malignant melanoma is one of the uncommon and highly aggressive tumors of the sinonasal cavity. Cytomorphological features in a metastatic lymph node may reveal a diagnosis of malignant melanoma. This case had nondiagnostic cytological and histopathological features, which could suggest malignant melanoma. Immunohistochemistry in such cases becomes the primary method for establishing the diagnosis of malignant melanoma at an uncommon site.
Keywords: Immunohistochemistry, lymph node, malignant melanoma, sinonasal
|How to cite this article:|
Gupta P, Bhardwaj M. Sinonasal malignant melanoma with metastasis: Immunohistochemistry meeting the diagnostic challenge. J Can Res Ther 2018;14:709-11
| > Introduction|| |
Primary sinonasal tract mucosal malignant melanomas are uncommon tumors. Inclusion-like prominent nucleoli, intra-nuclear cytoplasmic inclusions, and presence of melanin are helpful clues in making a cytological diagnosis along with other cytomorphological features in a metastatic lymph node. Our case reveals a poorly differentiated malignancy, which did not have the characteristic features of malignant melanoma and showed a mild degree of pleomorphism, inconspicuous nucleoli, and absence of melanin. It was the immunohistochemistry (IHC), which concluded the diagnosis of malignant melanoma.
| > Case Report|| |
A 51-year-old female presented to the fine-needle aspiration (FNA) clinic with multiple left cervical lymphadenopathy and complaints of a headache and anosmia for the past 15 days. The routine hematological and biochemical investigations were normal. Nasal endoscopy findings revealed left nasal cavity mass extending across the cribriform plate. The computed tomography (CT) scan brain and orbit revealed hyperdense enhancing polypoidal mass lesion in left sphenoidal, ethmoidal and frontal sinus, left nasal cavity and in the central frontal region with perifocal edema [Figure 1]a. There were nasal mucosa thickening and cribriform plate not delineated. The radiological impression was of a mass lesion extending from frontal region to left spheno-ethmoidal region or vice versa. Further, the positron emission tomography-CT revealed fludeoxyglucose (FDG) avid heterogeneously enhancing mass lesion in areas similar to those in CT as the primary lesion along with FDG avid metastatic left cervical lymph nodes.
|Figure 1:(a) Coronal view showing an enhancing mass lesion in the left nasal cavity and ethmoid sinus with extension (computed tomography scan). (b) Fine-needle aspiration smear show increased cellularity and cells arranged in clusters and singly scattered (papanicolaou, ×100). (c) The cells reveal mild pleomorphism and eccentric nucleus with finely granular chromatin and inconspicuous nucleoli. Background shows mature lymphocytes (papanicolaou, ×400). (d) Tumor cells in sheets with vesicular nucleus and inconspicuous nucleoli (H and E, ×400) IHC, inset reveals melan A positivity (DAB)|
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The FNA cytology (FNAC) was done from left cervical lymph node, which measured 2 cm × 1.5 cm in size. The smears were fixed in alcohol and air-dried and stained with papanicolaou and geimsa stain, respectively. The smears were cellular and revealed many atypical cells with mild pleomorphism and seen singly scattered, few clusters and occasional rosette-like arrangement [Figure 1]b. The cells were plasmacytoid with round to oval eccentric nucleus, fine granular chromatin, inconspicuous nucleoli, and a moderate amount of pale cytoplasm [Figure 1]c. Many stripped nuclei, few binucleate cells, occasional mitotic figures, and cells with cytoplasmic vacuolation were also noted. The background had small mature lymphocytes along with plasma cells and macrophages. Thus, the cytomorphological features were of metastatic poorly differentiated malignancy and a possibility of neuroendcrine carcinoma was suggested.
Histopathological examination of nasal punch biopsy showed solid sheets of tumor cells traversed by fine capillaries. The cells showed mild pleomorphism with round vesicular nuclei, inconspicuous nucleoli and moderate amount of vacuolated to the eosinophilic cytoplasm [Figure 1]d. Occasional mitosis was noted, and the stroma showed chronic inflammatory infiltrate.
A panel of IHC markers was put for the undifferentiated malignancy and showed positivity for S-100, Vimentin, NSE, CK, HMB 45, and melan A [Figure 1]d. Thus, final diagnosis was of malignant melanoma.
| > Discussion|| |
Sinonasal malignant melanomas account for <1% of all melanomas and <4% of sinonasal tumors. It is one of the uncommon and highly aggressive tumors of the sinonasal cavity. The anatomic distribution includes the nasal cavity, turbinate, the nasal wall, antrum, ethmoid sinus, vestibules, frontal sinus, and maxillary sinus. The symptoms are nonspecific, and they appear according to tumor location and thus, diagnosis is often delayed. The majority of patients present with nasal obstruction, epistaxis, and black nasal discharge. At initial presentation, these tumors are fairly advanced, due to the ample space available to accommodate their growth and the obscure anatomy of the sinuses. The presence of positive lymph node and advanced clinical stage at presentation are the poor prognostic indicators and, therefore, metastatic disease should always be excluded.,
Cytomorphological features on FNAC include marked cellularity with predominantly dissociated cell population, nuclear pleomorphism with plasmacytoid, polygonal or spindle cells, inclusion-like prominent nucleoli, intra-nuclear cytoplasmic inclusions, increased mitotic activity, variable number of bi- and multi-nucleated cells, and presence of melanin.
Pathologic diagnosis of melanoma relies often on the identification of intracellular melanin, which could be demonstrated in 50–70% of cases. The amelanotic lesions are challenging, and differential diagnosis should include a lymphoma, sarcoma, poorly differentiated carcinoma, small-cell carcinoma, schwannoma, plasmacytoma, olfactory neuroblastoma, and metastatic lesions from a cutaneous melanoma.,
In our case, there was the absence of key diagnostic features seen in malignant melanoma, which included melanin and prominent nucleoli. There was no intranuclear cytoplasmic inclusions and pleomorphism was mild. Thus, both the FNAC and histology were of a poorly differentiated malignancy and morphologically nonindicative of malignant melanoma. The presence of occasional rosette-like arrangement of plasmacytoid cells along with cellular details further raised the suspicion for neuroendocrine carcinoma. It now appears that a smearing artifact could have resulted in rosette like arrangement.
IHC plays an important role in making a confident diagnosis of morphologically inconclusive cases of malignant melanoma. Vimentin is the most consistent but the least useful diagnostically. Positivity for S-100 is nonspecific but being negative in most of the tumors that enter in the differential diagnosis, it has a higher sensitivity. HMB 45 is a much more specific marker than S-100 protein. Melan-A is positive in approximately 80% of melanomas. The positivity of MiTF is in the range of over 90%. Immunoreactivity for NSE, CD117, CD99, synaptophysin, polyclonal CEA and CK has also been reported infrequently.,
Our case reiterates that although malignant melanoma is uncommon sinonasal malignancy, it should be ruled out in metastatic lesions. It highlights that FNA smears and histological sections may not always yield diagnostic morphological details of malignant melanoma and also the pivotal role of IHC in the diagnosis of morphologically unsuspected cases.
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There are no conflicts of interest.
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