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!

A Diagnostic Dilemma

presented by Hamish Dunwoodie
Tracadie, New Brunswick

The patient is a 60 yo man who presented with a six months history of two asymptomatic erythematous nodules on the torso.  He has been in his usual state of health otherwise. No history of fever, chills or night sweats.

O/E:  There are two erythematous nodules located on the right abdomen and the left upper back.  They measure 3 - 4 cm in diameter. No other cutaneous findings.

Clinical Photos:

New Lesion 10.25,16 R, Upper Back)

Pathology:
A superficial and deep nodular and interstitial infiltrate of CD20 positive B-lymphocytes admixed with CD3 positive T-lymphocytes with slight preponderance of B-cells.  There is a scattering of CD30 positive lymphocyres.  There appears to be a Grenz zone.  Gene rearrangement studies are not indicative of either a clonal T or B cell lymphoproliferative disorder.

 

CD 3

CD 20

Lab: CBC, Chemistries, Serum protein electrophoresis all normal. IgG, IgM and IgG were all normal.

Diagnosis: The differential is between an atypical lymphoid infiltrate and a cutaneous lymphoma.  We are leaning towards the former.  Note: The last clinical photo was taken ~ 1 month after the others and shows progression.  We plan to excise this recurring tumor for help with diagnosis.

Questions:  

Should we treat? and if so how?

Should we follow with active surveillance?
Would any of you make a a more specific diagnosis?
Is any further testing indicated at this time?

Follow-up 2.3.16
The patient's lesions come and go.  All tests for systemic disease are negative.  New lesion (see photo) on left chest 2 cm in diameter seen today.  Will try to treat with clobetasol ointment.

10.16.16.  Old lesions have disappeared and new lesions develop.  Bo evidence of systemic disease.

Reference:
1. Atypical lymphoid proliferations: the pathologist's viewpoint. Hussein MR. Expert Rev Hematol. 2013 Apr;6(2):139-53. doi: 10.1586/ehm.13.4.

Abstract: Lymphoid proliferations are traditionally thought to be either benign conditions (reactive hyperplasia and lymphadenitis) or malignant lymphomas. However, not all lymphoid lesions at present can be precisely placed into one of these categories. 

2. Cutaneous B-cell lymphomas: 2015 update on diagnosis, risk-stratification, and management. Wilcox RA.  Am J Hematol. 2015 Jan;90(1):73-6. Free Full Text Online.