Keywords
cutaneous T-cell lymphoma - child - subcutaneous panniculitis-like T-cell lymphoma
- immunohistochemistry
Introduction
Almost 30% of pediatric primary care visits regard skin-related symptoms.[1] From the neonatal period throughout infancy, most of the skin lesions are benign,
and self-limiting.[2] Differential diagnosis of local skin inflammation usually includes trauma, insect
bites, atopic dermatitis, allergies, or inappropriate hygiene.[3] We report on an infant with a cellulitis of the thigh which turned out to be a subcutaneous
T-cell lymphoma.
Case Report
An 8-month-old girl with a 2-month history of superficial cellulitis of the anterior-medial
right thigh treated conservatively with ointments and local/oral antibiotics in basic
and dermatological care with no clinical improvement. Clinically, a large (10 × 5
cm) single, rectangular, flat, stiff infiltration with redness and peeling of the
skin was observed ([Fig. 1A]). The patient had a history of fever, sweating, and failure to thrive. Shortly before
hospitalization at our surgical unit in the pediatric oncology department, laboratory
tests showed elevated lactate dehydrogenase up to 869 U/L, aspartate transaminase
up to 153 U/L, alanine transaminase up to 113 U/L, and low C-reactive protein (1.04
mg/L). However, a magnetic resonance imaging (MRI) of a thigh confirmed the diagnosis
of a local inflammation with mildly enlarged lymph node of the groin. The intravenous
antibiotic was introduced causing mild local improvement, but the episodes of high
fever sustained. The patient was transferred to our pediatric surgery department for
treatment and surgical biopsy of the lesion ([Fig. 1B]).
Fig. 1 (A) The clinical picture of the right thigh after 2-months of conservative treatment;
(B) the lesion of the thigh after surgical biopsy (visible skin sutures) that confirmed
the diagnosis; (C) the same skin surface after 4 months of chemotherapy.
Histopathological examination showed a massive T-cell infiltration (cluster of differentiation
[CD]) CD3+, CD8+, CD5+, CD7+, CD4+ with sporadic CD99+, CD34+, TdT-, CD10-, CD56-
cells with numerous histiocytes, plasmatic cells and neutrophils. A very high proliferative
index was noticed (Ki-67+ > 70% of cells). A subcutaneous panniculitis-like T-cell
lymphoma (SPTCL) was diagnosed. Characteristic rimming of individual fat cells by
tumor cells with immunohistochemical staining specific for SPTCL was visualized in
our patient's specimen ([Fig. 2]).
Fig. 2 Hematoxylin and eosin staining (extension ×200). Skin biopsy showing subcutaneous
tissue with neoplastic infiltrate. The neoplastic cells range in size and have irregular,
hyperchromatic nuclei. The characteristic feature is the rimming of the neoplastic
cells surrounding individual fat cells.
The patient was transferred to the pediatric hematology department. Further staging
included a whole-body computed tomography (CT) scan with contrast enhancement (as
a whole-body MRI was unavailable and patient's general status was worsening). The
patient was introduced to a special chemotherapy protocol EURO-LB 2002 (prednisone,
6-mercaptopurine, and methotrexate) mildly adjusted to young age, with a good response.
During the first weeks of treatment, there was a Pseudomonas aeruginosa infection of the wound after the surgical biopsy which was treated with targeted
antibiotic therapy and later underwent surgical debridement with good wound healing
([Fig. 1C]). A control MRI of the thigh showed a significant improvement with reduction of
the lesion without enlargement of the surrounding lymph nodes.
Discussion
The SPTCL is a rare cytotoxic T-cell lymphoma representing less than 1% of non-Hodgkin
lymphomas.[4] It predominantly affects young adults and is uncommon in children.[5] SPTCL preferentially infiltrates subcutaneous tissue. As observed in our case, the
most common sites of localization are the extremities and trunk. Systemic symptoms
are observed in 50% of patients.[5] Our patient experienced intensive sweating and fever episodes for a significant
time period while treatment was only local without any further diagnostics. Definitive
diagnosis is based on a complex histopathological examination.[6] Nevertheless, it is crucial to combine the biopsy with information about clinical
symptoms to guide the pathologist in search of the accurate interpretation. In the
presented diagnostic process, in the communication between surgeon and pathologist
information about general symptoms as well as elevated parameters were very useful
and led to the final diagnosis.
Based on published case series, the morbidity, and mortality related to the development
of hemophagocytic syndrome that aggravates the prognosis, which optimistically was
not present in our patient.[7] Further molecular diagnostic tests determine T-cell receptor phenotype. The World
Health Organization (WHO) and European Organization for Research and Treatment of
Cancer (EORTC) in 2008 distinguished SPTCL with alpha beta T cells from primary cutaneous
gamma delta lymphoma (PCGD-TCL).[6] Immunophenotypic differences include CD56 positivity with lack of CD4 and CD8 in
PCGD-TCL. Such a division correlates with differences in prognosis, with much better
survival rates in SPTCL.[8]
The rarity of SPTCL resulted in a wide range of treatment strategies: from no treatment,
steroids, immunosuppressive therapy to multiagent chemotherapy.[8] In the presented case a chemotherapy protocol was introduced due to extensive general
symptoms and progression of the local state. If available, a whole-body MRI should
be considered in the staging process rather than a whole-body CT due to the high levels
of radiation connected with the latter.
In a skin lesion that is associated with systemic symptoms and responding untypically
to antibiotic treatment malignancy should be considered and biopsy not be postponed.
