Solitary Lymphocytic Tumor: Benign or Malignant?

A healthy 80-year-old  Chinese man presented with a 2-month history of a 6 x 6 cm erythematous plaque on the right forearm that had gradually increased in size. He saw a dermatologist 2 months ago, had a biopsy and was told it was an insect bite reaction. However, he did not recall any insect bite reaction.  I repeated his skin biopsy as it was not responding to treatment..

 

Clinical and Histopatological Photos

Pathology: Section shows epidermis with mild spongiosis. The dermis shows dense, superficial and deep perivascular infiltration of lymphocytes and plasma cells. There is no significant increase of eosinophils. The infiltrate extends along the sweat ducts, hair follicles and sebaceous glands. The superficial subcutaneous fat shows lymphocytes and plasma cells infiltration. The deeper dermis shows marked increased in eosinophils. There is no granulomatous lesion or atypical bizzare lymphocytes seen. The deeper dermis and subcutaneous fat are normal.  No granuloma or nerve hypertrophy seen.

INTERPRETATION
Reactive lymphoid proliferative disorder or lymphocytoma cutis.
No granuloma seen to suggest leprosy or cutaneous TB. 

Follow up with IHC stains.
CD3: CD20 showed mixed populations of the lymphoid cells.
CD10: positive weak for genimal centre
BCL2: negative for geminal centre
BCL6: positive for geminal centre
CD30 negative
EBER: negative
cMYC negative
EMA negative
Ki67 no marked increase in mitosis

Discussion: The pathologists concluded reactive lymphoid proliferative disorder or lymphocytoma cutis.

Questions: Is this benign or does it have a malignant potential?  Does he warrant further work up or perhaps follow up closely to watch his progression? Thanks for your input!

70 y.o. man with pre-auricular plaque

Presented by Dr. Henry Foong, Ipoh, Malaysia

The patient is a 70-yr-old man with a 2-month history of mildly pruritic skin eruption on the right preauricular area.  It has gradually increased in size and also felt "thicker" and more "lumpy".  He is otherwise in good health.

O/E shows a well demarcated hyperpigmented patch on the right preauricular area 7.5 cm x 3.0 cm.  on palpation it felt boggy. Regional nodes were not enlarged.  There was no facial nerve palsy.

 

Biopsy:

Microscopic:  Dense superficial and deep infiltrate of lymphocytes and plasma cells.  The deeper dermis shows markedly increases eosinophils. Angiolymphoid proliferation is absent as are granulomas or nerve hypertrophy.

 

Diagnosis:  My thoughts are lymphocytoma cutis versus angiolymphoid hyperplasia with eosinophila (ALHE)' but I have limited experience with these. 

Your suggestions would be appreciated.

 

Reference:

Burhan Engin, et. al. Lymphocytic infiltrations of face. Clin Dermatol. Jan-Feb 2014;32(1):101-8.
Abstract:  The immune system protects our organism and, of course, our skin from harmful factors. One of the key elements of the immune system is lymphocytes. Lymphocytes play a role in the pathogenesis of various skin diseases. Lymphocytic infiltrates are seen in many skin diseases. Some of the skin diseases characterized by lymphocytic infiltration show up in specific anatomic locations, whereas other entities can be placed in all areas of the body. The course of lymphocytic infiltrations of the face is variable and unpredictable, most often lasting from months to years. The most important diseases with lymphocytic infiltration of the face are pseudolymphomas. This review discusses various types of cutaneous pseudolymphomas and other diseases with lymphocytic infiltration mainly involving the face.