Introduction

Cutaneous T-cell lymphomas (CTCLs) are a group of rare lymphoproliferative disorders characterized by localization of the neoplastic lymphocytes to the skin at the time of presentation. Although Mycosis Fungoides (MF) and Sezary Syndrome (SS) make up the great majority of these diseases, there are many distinct entities that make up the differential diagnoses of cutaneous lymphoproliferative disorders₁. The group CTCLs other than Mycosis Fungoides, Sezary Syndrome and primary cutaneous CD30⁺ lymphoproliferations, constitute less than 10% of all CTCLs, with clinically aggressive behaviour and chemo therapy being treatment of choice in such cases₂. A rare variant of CTCL is peripheral T-cell lymphoma (PTCL) which was inappropriately termed as ‘non-epidermic T-cell lymphoma', since some degree of epidermal infiltration can occur. The diagnosis of PTCL by fine needle aspiration cytology (FNAC) is extremely difficult mainly due to rarity of disease, diverse cytomorphology and the difficulty in identifying abnormal T-cells₃.

We, hereby present FNA diagnosis of a case of peripheral T-cell lymphoma presenting with multiple nodules all over the body.

Case Report

A 52 years male presented with fever and multiple swellings all over the body for one month. On examination, he was found to have multiple, firm, subcutaneous nodules varying in diameter from 0.5-5.0 cm which were ulcerated at places (Fig. 1).

Figure 1

Figure 1: Patient having multiple subcutaneous nodules which are ulcerated at places.

There was no generalized lymphadenopathy or organomegaly. All the routine investigations including haematological investigations were within normal limits. FNAC was performed using 23 gauge needle from multiple sites and smears stained with May-Grunwald Giemsa (MGG) and Haematoxylin & Eosin (H&E) stains.

Cytological smears showed cellular aspirate comprising heterogenous population of lymphoid cells in varying stages of maturation along with few neutrophils, eosinophils and macrophages. There were atypical lymphoid cells, some of them showing large convoluted, bi to multilobated nuclei with clumped chromatin and prominent nucleoli with variable amount of cytoplasm (Fig. 2).

Figure 2

Figure 2: Smear showing heterogenous population of atypical lymphoid cells with irregular nuclei and variable amount of cytoplasm. A multinucleated cell is also seen. (MGG x 400)

Classical Reed-Sternberg cells were however not found in the smear. A diagnosis of primary cutaneous lymphoma with a possibility of T-cell lymphoma was made based on cytological, haematological and clinical findings.

A surgical biopsy from the lesion was performed along with immunohistochemical stains using a panel of antibodies. Immunohistochemistry showed CD4, CD8, CD3 and CD45 positivity (Fig. 3, 4, 5), loss of CD7 and was negative for CD30 and CD20, confirming the diagnosis of CTCL and categorizing it further as peripheral T-cell lymphoma. Patient was administered chemotherapy and is on regular follow up since then.

Figure 3

Figure 3: Immunohistochemical stain for CD45 showing membranous positivity.

Figure 4

Figure 4: Atypical lymphoid cells showing CD8 positivity

Figure 5

Figure 5: Immunoreactivity for CD3 in the lymphoma cells.

Discussion

Primary cutaneous T-cell lymphomas are malignant neoplasms of post-thymic mature T-lymphocytes that present as skin involvement with no evidence of extracutaneous disease at the time of diagnosis₂. Skin is the second most common site of extranodal non-Hodgkin's lymphoma. They are rare, representing 2% of all lymphomas₄.

CTCLs often have a completely different clinical behaviour, management and prognosis from systemic lymphomas. For that reason, primary cutaneous lymphomas have been classified as a separate entity by World Health Organization and European Organization for Research and Treatment for Cancer₂. CTCL include Mycosis Fungoides (MF) and its variants, Sezary Syndrome(SS) and various other subtypes. The diagnosis of CTCL and its further categorization is finally based on histopathology along with a panel of most relevant antibodies for T-cells (CD2, CD3, CD7, CD45) and their subtypes (helper/inducer CD4) and cytotoxic/supressor (CD8) and blast cells (CD30)₁.

The diagnosis of peripheral T-cell lymphoma on FNAC is extremely difficult and controversial mainly due to rarity of the disease and its morphological similarity with other reactive and neoplastic conditions. However, aspiration cytology coupled with ancillary techniques can be a useful diagnostic tool in the identification of such cases. PTCLs are further classified as pleomorphic small cell, pleomorphic medium cell, pleomorphic large cell and immunoblastic type, depending on the predominant cell population₁. At times, cytological smears in cases of PTCL comprise a polymorphic population of cells having atypical lymphocytes of variable size with large convoluted nuclei or Reed-Sternberg like cells in the background of normal lymphocytes, plasma cells, neutrophils, eosinophils and macrophages₅. Potential misdiagnosis can occur due to this heterogenous cellular pattern on cytology. The differential diagnoses include Hodgkin's lymphoma, Langerhan's cell histiocytosis, non-Hodgkin's lymphoma and even reactive lymphoid hyperplasia₅. In all cases, a diagnosis of MF and SS must also be ruled out by complete clinical evaluation and pathological findings and only when it does not fit into the common types of CTCL, it is classified as peripheral T-cell lymphoma.

Histopathology supported with a panel of antibodies is essential for a definite diagnosis in such cases₃,₆. In our case too, there was a cellular aspirate with a polymorphic population of cells with variable amount of cytoplasm having bi to multilobated nuclei in the background of normal lymphocytes, neutrophils and macrophages. The classical Reed-Sternberg cells were, however, absent. Considering the clinical and cytological features, a cytological possibility of T-cell lymphoma was suggested. Histopathology and immunohistochemical studies confirmed the FNA diagnosis and further categorized it as peripheral T-cell lymphoma.

Patients with PTCL, when compared with other T-cell lymphomas, have a poorer prognosis at the time of diagnosis, respond poorly to therapy and have shorter survival without sustained remissions₁. Thus, it is important for the cytopathologists to recognize this heterogenous group of malignancy for appropriate and early management of these patients.

Correspondence to

Dr. Sanjay Kumar 4/9J, Medical Enclave, PGIMS, Rohtak-124001 (Haryana), INDIA e-mail : drsanjayk@rediffmail.com Tel. No.: +91 1262 211515 Fax no.: +91 1262 211308