Sir,

A 70-year-old male was referred to our department due to a progressive rash that first appeared seven months previously. He had a medical history of hypertension and hyperlipidemia, but without hepatitis B or C. A physical examination revealed scaly erythema on the upper extremities, erythema and blisters on the dorsa of the hands (Fig. 1), and hemorrhagic blisters on the lower extremities. A biopsy specimen taken from the erythema on the elbow showed irregular extensions of epidermal protrusions, lymphocytic infiltration under the epidermis, liquefaction degeneration of the basal layer, and individual cell keratinization in the epidermis (Fig. 2a). Another biopsy specimen taken from a blister on the dorsum of the hand revealed lymphocytic infiltration under the epidermis, forming subepidermal blisters (Fig. 2b). No deposition of immunoglobulins was observed in the basement membrane zone by direct immunofluorescence. Amlodipine and atorvastatin, which the patient had been receiving for hypertension and hypercholesterolemia, were discontinued, and dental metal removal was performed; however, no improvement was observed. Both topical corticosteroids and phototherapy were ineffective, and treatment with etretinate was discontinued due to liver dysfunction after only two weeks of intake. Two years after the diagnosis of bullous lichen planus (LP), he complained of general fatigue, and blood tests showed elevated C-reactive protein levels. Whole-body CT revealed multiple lymphadenopathies. A lymph node biopsy from the neck led to a diagnosis of Hodgkin’s lymphoma (Fig. 3). The patient was admitted to another hospital for further treatment.

	Figure 1: Clinical features of the elbow and the dorsum of the left hand.
	Figure 2: (a) Histopathology of the erythema on the elbow showing subepidermal lymphocytic infiltration, a poorly defined epidermal basal layer, and necrosis of epidermal cells (H&E, 200×). (b) Histopathology of a blister on the dorsum of the hand showing subepidermal lymphocytic infiltration and blister formation (H&E, 200×).
	Figure 3: Atypical lymphocytes increased and Reed–Sternberg cells observed (H&E, 400×).

Bullous LP generally tends to appear on the oral mucosa and lower extremities, with blisters appearing near or over existing LP lesions [1]. In the present case, blisters were seen mainly on the lower extremities. In addition, the biopsy revealed subepidermal blisters, and direct immunofluorescence revealed no deposition in the basement membrane zone. The patient was diagnosed with Hodgkin’s lymphoma about two years after the diagnosis of bullous LP. Concurrent occurrence of LP and malignant lymphoma has been reported in only three cases in the English literature, including the present case (Table 1) [2,3]. The patients were two males and two females, and the malignant lymphomas included non-Hodgkin’s lymphomas (n = 2) and Hodgkin’s lymphoma (n = 1) (one was unknown). Except for the present case, malignant lymphoma preceded the occurrence of LP, and the time from the diagnosis of malignant lymphoma to LP onset ranged from 1 month to 6 years. By contrast, in the present case, LP preceded the development of the lymphoma by two years.

Table 1: Report of malignant lymphoma combined with LP.

Various co-morbidities have been reported for LP, including hepatitis C virus infection, autoimmune diseases, internal malignancies, dyslipidemia, and viral infections [4]. Among over 13,000 reported female LP patients in Finland, 31 patients died of malignant lymphoma, among which 27 were non-Hodgkin’s lymphomas and 4 Hodgkin’s lymphomas [5], both showing increased standardized mortality ratios compared to the general population. Although the co-existence may be fortuitous in the present case, further accumulation of similar cases is necessary to determine the relationship between bullous LP and a hematologic malignancy.

REFERENCES

1.  Liakopoulou A, Rallis E. Bullous lichen planus:A review. J Dermatol Case Rep. 2017;11:1-4.

2.  Feuerman EJ, Sandbank M. Lichen planus pemphigoides with extensive melanosis:Occurrence in a patient with malignant lymphoma. Arch Dermatol. 1971;104:61-7.

3.  Helm TN, Camisa C, Liu AY, Valenzuela R, Bergfeld WF. Lichen planus associated with neoplasia:A cell-mediated immune response to tumor antigens?J Am Acad Dermatol. 1994;30:219-24.

4.  Gorouhi F, Davari P, Fazel N. Cutaneous and mucosal lichen planus:A comprehensive review of clinical subtypes, risk factors, diagnosis, and prognosis. Sci World J. 2014;2014:742826.

5.  Halonen P, Jakobsson M, Heikinheimo O, Gissler M, Pukkala E. Incidence of lichen planus and subsequent mortality in Finnish women. Acta Derm Venereol. 2020;100:adv00303.