Kaposi Sarcoma Revealing a Myelodysplastic Syndrome.

Sir,

Kaposi sarcoma (KS) is a vascular proliferation associated with HHV8. First described among HIV patients, four different subtypes have been later defined.[1] Immunosuppression-associated form is usually seen after organ transplantation or immunosuppressive therapy. However, it can be due to idiopathic immunodepression or severe affections such as neoplasm. We report the case of KS revealing a myelodysplastic syndrome (MDS).

A 73-year-old female patient with history of high blood pressure and chronic obstructive pulmonary disease presented with an 8-year history of erythematous-violaceous plaques on the nose and multiple nodules on the lower legs [Figure 1]. The diagnosis of KS was confirmed by histology [Figure 2] and immunohistochemical detection of HHV8 [Figure 3]. The HIV serology was negative. The patient wasn't under immunosuppressive therapy. Initially, external radiotherapy was indicated. However, it was interrupted after 6 sessions due to secondary edema. Two years later, she consulted for the extension of the lesion on the left leg with the appearance of violaceous nodules on the abdomen, the right cheek, the right shoulder and a violaceous plaque on the palate [Figure 4]. Multiple nodules of different sizes appeared on the upper left leg. Some of them were multilobed [Figure 5]. The left feet had a verrucous and hyperkeratotic aspect with toenail dystrophy [Figure 6]. A digestive localization of KS was ruled out using gastrointestinal endoscopy. The complete blood count revealed anemia associated to vitamin B12 deficiency. She was treated with intramuscular vitamin B12. Despite a good treatment adherence, the hemoglobin level decreased to 6 g/dL with the onset of leukopenia and severe lymphopenia. A bone narrow biopsy allowed the diagnosis of MDS which explained the extensive form of KS. She was then referred to the hematology department and received regular blood transfusions. Bleomycin, the only systemic therapy available for KS in our country, was contraindicated because of her pulmonary disease. Thus, the treatment was limited to cryotherapy each 15 days and support stocking with a slight improvement.

Figure 1

Multiple erythematous-violaceous nodules of the leg

Figure 2

Histologic features: a (HE x2), b (HE x10): Dermal proliferation of spindles shaped cells with slit-like spaces filled with red blood cells

Figure 3

Immunohistochemical detection of the HHV8 (HE × 10): Spindle cells are positive for the human herpesvirus type 8

Figure 4

Violaceous plaque on the palate

Figure 5

Erythematous-violaceous and skin-colored nodules on the upper left leg. Some of the nodules are multilobed

Figure 6

Verrucous and hyperkeratotic aspect of the left feet

KS occurring with a primary neoplasm is rare. It might be a solid tumor, cutaneous neoplasm, or hematologic malignancy.[2] In our case, KS revealed an MDS, a group of hematologic diseases consisting of dysplastic hematopoiesis that leads to peripheral cytopenia. KS either appears during the course of MDS or is the first symptom revealing MDS. This association was reported twice in the literature.[34] It can be explained by the severe immunodepression secondary to MDS. In fact, patients with MDS have a high risk of severe infections. The most important factor is neutropenia. However, other immune defects such as lymphocyt B, T, and NK defects or abnormal neutrophil function were incriminated.[5] Our patient presented lymphopenia due to the MDS. Its association to her late age explains the immunodepression that led to an extensive form of KS. Indeed, HIV serology was negative. The classic form of KS was also unlikely as it had an extensive evolution with atypical distribution. Thus, hematologic malignancies such as MDS must be suspected in case of an extensive form of KS with complete blood count abnormalities.

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