Facial Nodule: What is Your Diagnosis?

A 56-year-old man came with a complaint of asymptomatic, elevated, reddish skin lesion over the left cheek [Figure 1] for the 15 years. Initially, the lesion was small in size, gradually increasing in size for the 15 years, and was not associated itching or pain. There was no history of insect bite, trauma, injections, and drug intake. On examination, 1 × 1 cm, circumscribed, erythematous nodule present over the left cheek. It was firm in consistency, non-tender, easily movable, not attached to underlying structures, and distinct from surrounding skin. We kept differential diagnosis of lymphoma cutis, Jessemer's lymphocytic infiltration of skin, dermatofiroma, pilomatricoma.

Figure 1.

A solitary nodule on the cheek

Microscopic examination showed thinned out epidermis with diffuse, heavy lymphocytic infiltrate with few plasma cells in the dermis, occasional eccrine glands were seen.[Figure 2]

Figure 2.

(a) Thinned out epidermis, heavy infiltrate of lymphocyte throughout the dermis ×100 magnification, (b) Lymphocytic infiltration ×400 magnification

Features were consistent with.

Question

What is your diagnosis?

Answer

Cutaneous lymphoid hyperplasia.

Discussion

Cutaneous lymphoid hyperplasia (CLH), first described in 1894, is a benign, reactive, lymphocytic process of unknown cause that occurs most often in adults and less commonly in children. CLH represents an exaggerated local immunologic reaction to an often unrecognized trigger, such as vaccinations, arthropod bites, tattoos, zoster, medications, and infections such as Borrelia burgdorferi and Leishmania panamensis.[1,2] Clinically characterized by isolated or few erythematous nodules or plaques, mainly on the face and extremities. Generally, the patients are in good health without evidence of systemic involvement. Lesions are asymptomatic, and the clinical course is characterized by spontaneous remission.[3]

Typically, CLH characterized by solitary, firm, slightly tender, erythematous to violaceous papule or nodule on the head, neck, or upper extremities with no surface changes.[1] Histology usually reveals a superficial and deep nodular or diffuse polymorphic infiltrate comprising lymphocytes, histiocytes, and occasional plasma cells and eosinophilic leukocytes.[4] Lymphoid follicles with germinal centers surrounded by a mantle might be noted. Pseudolymphoma has to be distinguished from cutaneous lymphomas by the combination of clinicopathological correlation, histochemical studies, and, in selected cases, gene re-arrangement studies.[3] Immunoperoxidase studies might be used to confirm the polymorphic nature of the infiltrate, including the presence of CD4-positive and CD8-positive T lymphocytes, CD20-positive B lymphocytes, and CD68-positive histiocytes. Clonality has been reported in CLH, but it currently remains unclear if this is related to the rare occasions when CLH progresses to lymphoma.[4]

Differential Diagnosis

Differential diagnosis of CLH includes pyogenic granuloma, epidermal inclusion cyst, and Spitz nevus. Pyogenic granuloma usually presents as a solitary, rapidly growing, red, vascular lesion on the face or fingers. Differentiation from CLH is clinically possible, based on the lesion's soft consistency, rapid growth, and recurrent bleeding. An epidermal inclusion cyst is a benign, cutaneous cyst that commonly presents as a skin-colored or red inflamed papule or nodule on the face or trunk. Differentiation from CLH is based on its soft consistency. Spitz nevus is a melanocytic nevus that usually presents as an asymptomatic, small (less than 1 cm), pink to red papule on the faces or extremities of children and adolescents. Clinical differentiation might be difficult, although the small size and smooth surface of Spitz nevus can be helpful.[4] If in doubt, Spitz nevus as well as pyogenic granuloma and epidermal inclusion cyst can be differentiated easily from CLH histologically.[1,4] Another important (and histologic) differential diagnosis of CLH is lymphoma cutis.[1] Differentiation is important because lymphoma cutis is a manifestation of lymphoma, whereas CLH is not. Microscopic features that are helpful in differentiating CLH from lymphoma cutis include the presence of reactive germinal centers and the polymorphic nature of the infiltrate, including the mixed population of B and T lymphocytes.[4]

Management

A conservative approach should be entertained, as most cases spontaneously resolve within a few weeks to months. If the lesion persists, then a punch biopsy is indicated to confirm the diagnosis and to rule out other conditions; it might also be curative. If a histologic diagnosis of CLH is confirmed, persistent cases with localized lesions might benefit from antibiotics, intralesional and systemic corticosteroids, excision, radiotherapy, and immunosuppressants. Treatment depends on the assessment and biologic behavior, which is usually benign. Molecular biologic analysis has shown that a significant proportion of cases harbor occult B- or T-cell clones (clonal CLH). Progression to overt cutaneous lymphoma has been observed in a minority of cases. Patients with clonal populations of B or T cells and persistent lesions should be closely observed for emergence of a lymphoma.[1,3]