A Difficult-to-Diagnose Case of Subcutaneous Panniculitis-Like T-Cell Lymphoma with a Fatal Outcome

Dear Editor,

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic αβ T-cell lymphoma characterized by the primary involvement of subcutaneous tissue mimicking panniculitis. It is a predominant cluster of differentiation 3 (CD3+/CD4-/CD8+) phenotype in the World Health Organization-European Organisation for Research and Treatment of Cancer (WHO-EORTC) classification for cutaneous lymphomas.[1] It accounts for less than 1% of all cutaneous lymphomas with a wide spectrum of clinical presentations and may require repeat biopsies to diagnose. Here, we report a case of SPTCL and describe the challenges in recognizing and properly diagnosing the disease.

A 41-year-old female presented with a one-month history of asymptomatic erythematous plaques of size 1 × 1 cm² over the left ala of the nose and upper back of the trunk for the past 3 months and painless swellings of size 2 × 2 cm² over the bilateral temporal region of the face and swelling of size 1 × 1 cm² over the upper lip [Figure 1]. Also, there was a single enlarged tender cervical lymph node in the anterior triangle of the neck.

Figure 1.

(a) Showing erythematous plaque over the nose and (b) swelling over bilateral temporal regions, right side of the upper lip on the first visit

Upon investigations, eosinophilia and raised erythrocyte sedimentation rate were noted. Fine needle aspiration cytology of the left cervical lymph node was reported as “non-necrotizing granulomatous lymphadenitis”. Biopsy showed a dense peri adnexal collection of lymphocytes, histiocytes and some epithelioid cells. Further, the patient was lost to follow-up.

After 8 months, the patient was admitted to the medicine ward with complaints of continuous high-grade fever, shortness of breath for 1 week and multiple skin lesions.

On general examination, conjunctival pallor was noted. Cutaneous examination showed multiple erythematous nodules and a few plaques of varying sizes with central crusting and necrosis distributed over the face, both upper and lower limbs [Figure 2]. Also, multiple bullae with the erythematous base were present over the dorsum of both hands and forearms and a few targetoid lesions on the palms and soles [Figure 3].

Figure 2.

Showing multiple erythematous plaques with necrosis all over the face

Figure 3.

Showing multiple vesicles, bulla and erythematous plaques on both dorsum of hands, palms, and soles

On ultrasound, mild hepatosplenomegaly was reported. The peripheral smear showed atypical large cells associated with anaemia, eosinophilia, neutrophilia, and thrombocytopenia, suggestive of high-grade lymphoma with infiltrations [Figure 4]. On histopathological examination, features of “panniculitis with areas of necrosis and rimming of neoplastic cells around individual fat cells” are observed [Figure 5]. Immunohistochemistry (IHC) was positive for CD3 and CD8 and negative for CD4, CD7, and CD56 [Figure 6].

Figure 4.

Showing peripheral smear with the spill of atypical large cells, plenty of eosinophils and neutrophils

Figure 5.

Histopathology with H and E stain 40X magnification (a) Lymphoid collection in the dermis and subcutaneous tissue (b) showing dense neoplastic cells along with necrosis (c) showing tropism for adipocytes as neoplastic cells surround the fat cells in a lacelike pattern (d) showing characteristic rimming of neoplastic cells around fat lobules. H and E = Hematoxylin and Eosin

Figure 6.

Immunohistochemistry showing (a) CD3 positive cells and (b) CD8 positive cells. CD = cluster of differentiation

The final diagnosis was made as SPTCL. Unfortunately, the patient expired even before the biopsy was reported.

SPTCL presents with multiple asymptomatic subcutaneous nodules and plaques, predominantly affecting the legs or trunk and less commonly, the face or arms. On the contrary, they were the initial sites in our case.

The other conditions which can have plaques and nodules with ulceration include lupus panniculitis, cytophagic histiocytic panniculitis, pancreatic panniculitis, nodular vasculitis, and erythema nodosum leprosum. Clinically and histopathologically, SPTCL is difficult to distinguish from lupus erythematosus panniculitis[2] and can be misinterpreted. In HPE, the rimming of certain fat compartments by neoplastic cells is the distinctive feature of SPTCL that is present in our case [Figure 5], suggesting that this lymphoma had a peculiar tropism for adipocytes[3].

With a wide range of clinical presentations in SPTCL, lesion biopsy is tantamount to diagnosis. In the early stages, the infiltrate might not show significant atypia, and the classical histopathology may not be evident later when the lesions are regressing. Similarly, in our case, there are no features suggestive of lymphoma in the primary biopsy, emphasizing the value of regular follow-up with biopsy for diagnosis.

Lymphomas expressing T-cell receptor–αβ are usually restricted to the subcutaneous tissue[4]. The unique feature here was that, though IHC is diagnostic of αβ TCL, there was focal lower dermal spread, which contrasts most of the previous reports of dermal sparing. Also, this conflicts with the γδ–TCL variant, where involvement of the epidermal/dermal tissue may also exist. Another noteworthy point of this case is the spillage of neoplastic cells into peripheral blood [Figure 4].

SPTCL has an indolent course with a 5-year overall survival rate of 85% to 91%, especially in the absence of hemophagocytic lymphohistiocytosis (HLH). As there is no pathognomonic finding or gold standard test for the diagnosis of HLH, a composite probability score (H Score) has been proposed by Fardet et al. for an early diagnosis of HLH.[5] Our case had an H Score of 111, which was the probable reason for the fatal outcome. We could not confirm further parameters of HLH as the patient expired. Improvement in survival might be expected with early diagnosis and treatment.

SPTCL is a rare entity and can be easily overlooked if its possibility is not considered in the differentials of patients with panniculitis; thus, necessitating thorough examination is crucial. Clinicians should remain vigilant about HLH in patients presenting with constitutional symptoms to prevent poor outcomes.

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Conflicts of interest

There are no conflicts of interest.