ALK positive lymphohistiocytic variant of anaplastic large cell lymphoma in an adult.
OBJECTIVE
The lymphohistiocytic (LH) variant of anaplastic large cell lymphoma (ALCL) has, for a long time, been considered typical of children and adolescents. The aim of this study is a detailed characterization of a case of this peculiar ALCL subtype affecting an adult patient.


METHODS
A 36-year old male presented with diffuse adenopathy and systemic symptoms (high fever, anorexia, asthenia); a diagnosis of CD30+/ALK+ ALCL, LH variant, was morphologically suspected and corroborated by immunohistochemistry that was crucial for the definitive diagnosis and subtyping.


RESULTS
The neoplastic population consisted of cells highly variable in size and shape but more often isolated and largely obscured by a predominant reactive cellular infiltrate of histiocytes and plasma cells. The lymphoma cells exhibited a null non-B non-T antigenic profile, but reacted strongly for the Ber-H2/CD30, EMA, ALKc anti-TIA-1 monoclonal antibodies. The patient underwent chemotherapy plus bone marrow transplantation and, one year after diagnosis, he is well and in complete remission.


CONCLUSIONS
Our findings provide additional evidence that: a) ALK+ lymphoma represents a single disease with a broad spectrum of morphology; b) clinicians and pathologists should be aware of the possible occurrence of LH variant of ALK+ ALCL also in adults in whom a favorable response to therapy may be expected despite systemic disease and an aggressive clinical presentation.
Paulli
M
M
Anatomic Pathology Department, IRCCS Policlinico S. Matteo, via Forlanini 14, 27100 Pavia, Italy. apat@unipv.it
Vallisa
D
D
Viglio
A
A
Boveri
E
E
Kindl
S
S
Vassallo
G
G
Magrini
U
U
Cavanna
L
L
D000328:Adult; D000077548:Anaplastic Lymphoma Kinase; D015616:Histiocytosis, Non-Langerhans-Cell / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D066298:In Vitro Techniques; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D008297:Male; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases
C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases