Clinical Dermatology Review

CASE REPORT
Year
: 2017  |  Volume : 1  |  Issue : 1  |  Page : 22--24

Cutaneous pseudolymphoma: An enigma


BM Shashikumar, MR Harish, Kirti P Katwe, M Kavya 
 Department of Dermatology, Mandya Institute of Medical Sciences, Mandya, Karnataka, India

Correspondence Address:
B M Shashikumar
Department of Dermatology, Mandya Institute of Medical Sciences, Mandya, Karnataka
India

Abstract

Cutaneous pseudolymphoma, also called lymphoid infiltrates of the skin mimicking lymphomas, is defined as reactive polyclonal benign lymphoproliferative process predominantly composed of either B-cells or T-cells, localized or disseminated. A 62-year-old male presented with multiple asymptomatic swellings over the posterior aspect of the left ear of 1-year duration. On examination, multiple nodules were present over the left retroauricular area, 2 of which were skin colored, firm, and nontender. Histopathology revealed pseudolymphoma with the features of a dense diffuse and nodular infiltrate of small and large lymphocytes and histiocytoid cells involving the whole of reticular dermis and extending to subcutis. A patch test was done using Indian standard battery series showed positive reaction - 2+ for paraphenylenediamine. A diagnosis of cutaneous pseudolymphoma was made. The lesions were treated with intralesional Triamcinolone acetonide injection 10 mg/ml for 2 sittings, 3 weeks apart following which there was remission of the nodules. Pseudolymphomas are benign but persistent lymphoid proliferations in the dermis, which may be difficult to distinguish from a low-grade malignant lymphoma. Pseudolymphomas are classified according to the histological components into B-cell and T-cell variants. So far no case of cutaneous pseudolymphoma suggestive of insect bite with coincidental paraphenylenediamine allergy has been reported. Hence, this case is reported as its histopathology was suggestive of pseudolymphoma secondary to insect bite reaction.



How to cite this article:
Shashikumar B M, Harish M R, Katwe KP, Kavya M. Cutaneous pseudolymphoma: An enigma.Clin Dermatol Rev 2017;1:22-24


How to cite this URL:
Shashikumar B M, Harish M R, Katwe KP, Kavya M. Cutaneous pseudolymphoma: An enigma. Clin Dermatol Rev [serial online] 2017 [cited 2020 Aug 14 ];1:22-24
Available from: http://www.cdriadvlkn.org/text.asp?2017/1/1/22/196949


Full Text

 Introduction



Cutaneous pseudolymphoma, also called lymphoid infiltrates of the skin mimicking lymphomas, is defined as reactive polyclonal benign lymphoproliferative process predominantly composed of either B-cells or T-cells, localized or disseminated. [1] Pseudolymphoma is not a specific disease but an inflammatory response to known or unknown stimuli. However, pseudolymphoma term is reserved for idiopathic cases where inciting cause in unknown. [2] Here, we report a case of cutaneous pseudolymphoma with positive patch test for paraphenylenediamine.

 Case Report



A 62-year-old male presented with multiple asymptomatic swellings over the posterior aspect of the left ear of 1-year duration. The lesion began as a solitary swelling, which was insidious in onset; it gradually progressed in number to 4 over a period of 1 year. The patient gave no history of chronic drug intake, localized trauma, or insect bite.

On local examination, multiple nodules were present over the left retroauricular area, 2 of which were skin colored, firm, and nontender [Figure 1]a. There were two other yellowish colored nodules, soft in consistency, nontender with multiple open comedones, milia and pitsover the surface of the nodules suggestive of sebaceous cysts [Figure 1]b. Multiple, erythematous scaly plaques were present bilaterally anterior to the right and left tragus. The systemic examination was normal.{Figure 1}

Lepromatous leprosy, sarcoidosis, histiocytosis, and lupus vulgaris were considered for differential diagnosis. A skin biopsy was done, and the histopathology revealed pseudolymphoma with the features of a dense diffuse and nodular infiltrate of small and large lymphocytes and histiocytoid cells involving the whole of reticular dermis and extending to subcutis [Figure 2]a. The nodules showed the formation of lymphoid follicles though in the majority of the nodules the shape of the lymphoid follicle is irregular and the number of blood vessels is increased within the nodules. The subepidermal zone was completely spared by the lymphocytes. A few eosinophils were seen scattered within the infiltrate [Figure 2]b.{Figure 2}

A patch test was done using Indian standard battery series showed positive reaction -2+ for paraphenylenediamine [Figure 3].{Figure 3}

Thus, on the basis of above-mentioned tests, a diagnosis of cutaneous pseudolymphoma was made. The lesions were treated with intralesional Triamcinolone acetonide injection 10 mg/ml for 2 sittings, 3 weeks apart following which there was remission of the nodules [Figure 4].{Figure 4}

 Discussion



Pseudolymphomas are benign but persistent lymphoid proliferations in the dermis, which may be difficult to distinguish from a low-grade malignant lymphoma. Confusion between pseudolymphoma and lymphoma can arise if a biopsy is submitted to the pathologist without an adequate history. Pseudolymphomas are classified according to the histological components into B-cell and T-cell variants. T-cell pseudolymphomas arise as a form of adverse drug reaction, persistent contact dermatitis, persistent nodular scabies, and arthropod bites. B-cell pseudolymphomas may arise from Borrelia burgdorferi infection, tattoos, postvaccination, trauma, acupuncture, and within scars after herpes zoster. However, many a time cause cannot be identified and termed as idiopathic pseudolymphoma. Both T and B cell pseudolymphomas present as multiple cutaneous nodules. On histopathology, the salient feature of a pseudolymphoma is the presence of T or B cell lymphoid proliferations. The degree of cellular atypia is minimal, and few mitotic figures may be seen. [3]

Terada reported a case of cutaneous pseudolymphoma in a 78-year-old male with itchy skin swellings over the arm. Immunohistochemistry revealed constituent cells were positive for both B cells including plasma cells and T cells. The causative agent was unknown. [1] In our case too, the etiology was not known. However, histology showed a lot of eosinophilic infiltrate suggestive of insect bite, but patient denied such insect bite history. Furthermore, there was an incidental finding of positive patch test for paraphenylenediamine where these may be the causative agent, but the patient denied use of hair dyes.

Prabhu et al. reported a case of cutaneous pseudolymphoma resembling a nevus in a middle-aged male. The histological evidence of top heavy dermal, mixed cellular infiltrate, absence of pigmentation and blast cells revealed a diagnosis of pseudolymphoma. [2] In this case too, only histology was suggestive of the diagnosis of cutaneous pseudolymphoma as in our case.

A similar case report of paraphenylenediamine induced pseudolymphoma was reported in a patient, who presented with itchy nodular lesions over moustache area, treatment was stoppage of hair dye use and topical steroids which led to complete remission without any relapse on follow-up. [4] In the present case, as the patient did not give any history of hair dye use, intralesional steroid treatment was given following which there was complete remission.

Several cases of pseudolymphoma have been reported in the past secondary to drugs, contact dermatitis, Borrelial infection and with unknown etiology but so far no case of cutaneous pseudolymphoma suggestive of insect bite with coincidental paraphenylenediamine allergy has been reported. Hence, this case is reported as its histopathology was suggestive of pseudolymphoma secondary to insect bite reaction.

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Conflicts of interest

There are no conflicts of interest.

References

1Terada T. Cutaneous pseudolymphoma: A case report with an immunohistochemical study. Int J Clin Exp Pathol 2013;6:966-72.
2Prabhu V, Shivani A, Pawar VR. Idiopathic cutaneous pseudolymphoma: An enigma. Indian Dermatol 2014;5:224-6.
3Whittaker SJ. Cutaneous lymphomas and lymphocytic infiltrates. In: Burns T, Breathnach S, Cox N, Griffiths C, editors. Rook's Textbook of Dermatology. 8 th ed Oxford: Blackwell Publishing; 2010. p. 57.53-4.
4Sequeira FF, Jayaseelan E, Stephen J. Paraphenylenediamine-induced cutaneous pseudolymphoma. Indian J Dermatol 2014;59:424.